MULTIPLE PATTERNING USING IMPROVED PATTERNABLE LOW-k DIELECTRIC MATERIALS

ABSTRACT

A method of double patterning a semiconductor structure with a single material which after patterning becomes a permanent part of the semiconductor structure. More specifically, a method to form a patterned semiconductor structure with small features is provided which are difficult to obtain using conventional exposure lithographic processes. The method of the present invention includes the use of patternable low-k materials which after patterning remain as a low-k dielectric material within the semiconductor structure. The method is useful in forming semiconductor interconnect structures in which the patternable low-k materials after patterning and curing become a permanent element, e.g., a patterned interlayer low-k material, of the interconnect structure.

FIELD OF THE INVENTION

The present invention relates to semiconductor device processing, andmore particular to methods for multiple patterning of a semiconductorstructure using improved patternable low dielectric constant (low-k)materials as both a photoresist material and as a permanent low-kmaterial of the semiconductor structure. Even more particularly, thepresent invention provides methods to pattern very small permanentdielectric features that are not possible with a conventional singleexposure lithographic process.

BACKGROUND

Due to the increased demand for highly integrated semiconductor devices,techniques of integrating more semiconductor devices into a smaller areahave become strongly relied upon. The integration of many semiconductordevices onto a small area includes downscaling the semiconductor devicesto be formed on the semiconductor wafer Moreover, as the integrationdensity of semiconductor devices increases, the line width and spacingof circuit elements in the semiconductor devices must decreaseaccordingly.

In general, electronic features of a semiconductor device are formedusing patterns created by a photolithography process or processes.Patterns used to form circuit elements with spacing and/or line widthsless than a predetermined minimum amount are referred to as “fine pitch”patterns. One of the main factors that determine the minimum pitch ofpatterns that can be formed by a photolithography process is the type oflight source used in the photolithography process. For example,conventional photolithography processes commonly use light sources suchas krypton fluoride (KrF) or argon fluoride (ArF) lasers, which haverespective wavelengths of 248 nm or 193 nm. Unfortunately, theresolution of these KrF or ArF lasers is not high enough to produce finepitch patterns required in many advanced semiconductor devices.

Because of this problem, the formation of fine pitch photoresistpatterns is currently the subject of much research. One proposed methodfor forming fine pitch patterns is a double patterning method. Doublepatterning, or more generally, multiple patterning is a class oftechnologies developed for photolithography to enhance the featuredensity. In the semiconductor industry, double patterning may be used asearly as the 45 nm node and may be the primary technique for the 32 nmnode and beyond.

There are several types of double patterning technologies including, forexample, double exposure/double etching or litho-etch-litho-etch (LELE).In such a technique, a first photoresist is first applied to a structureincluding, from top to bottom, a hard mask, an underlayer and asubstrate. After applying the first photoresist to the structure, afirst pattern is provided utilizing a conventional lithography step.Following patterning of the first photoresist, the first pattern istransferred to the hard mask utilizing a first etching step that stopson a surface of the underlayer. A second photoresist is then applied tothe patterned structure and is exposed to a second patterning step. Thesecond patterning step provides a second pattern into the secondphotoresist that lies between the first pattern provided in the firstpatterning and etching step. After second patterning, the second patternformed in the second photoresist is transferred to the structureutilizing a second etching step. The second etching step removes exposedportions of the hard mask, while also stopping on the surface of theunderlayer. The patterned second photoresist is removed and thereafterthe first and second patterns provided in the hard mask are transferredto the underlayer utilizing a third etching step.

One problem with conventional double exposure/double etching is that itrequires complex processing including the use of two layers of resistand a hard mask, Additionally, many steps are required to deposit andremove the photoresists and hard mask employed in a conventional doubleexposure/double etching process. Yet another problem with theconventional double patterning techniques is that all the patternsformed are on sacrificial photoresists and/or a hard mask, and, as such,additional etch steps are required to transfer these patterns to theunderlying substrate. These transfer steps are costly and often degradethe performance of the underlying structures/devices.

A less complex double patterning method involves direct patterning oftwo photoresists consecutively. This process is sometime calllitho-litho-etch (LLE) double patterning. In this double patterningscheme, a first photoresist is first applied to a structure including,from top to bottom, an antireflective coating and a substrate. Afterapplying the first photoresist to the structure, a first pattern isformed utilizing a conventional lithography step. Following patterningof the first photoresist, a second photoresist is applied directly ontothe first patterned photoresist and is subjected to a second patterningstep. The second patterning step provides a second pattern into thesecond photoresist that lies between the first patterned photoresistprovided in the first patterning step, thus providing fine pitch (doublethe resolution) pattern. This fine pitch photoresist pattern isthereafter transferred to the underlying substrate utilizing an etchingstep.

One of the major problems with this litho-litho-etch double patterningprocess is the incompatibility of conventional resists. That is, duringthe double patterning process, the first photoresist dissolves duringthe formation of the second photoresist, causing deformation of thefirst pattern.

In view of the above, there is a need for providing a new and improvedmultiple patterning process in which very small permanent features canbe formed which does not require sacrificial photoresists and theetching steps of conventional double patterning processes.

SUMMARY

The present invention provides a method of multiple patterning asemiconductor structure with a photo-patternable low dielectric constant(low-k) material which after patterning becomes a permanent part of thesemiconductor structure. More specifically, the method of the presentinvention forms a patterned semiconductor structure with small features,which are difficult to obtain using conventional single exposurelithographic processes. The method of the present invention includes theuse of patternable low-k materials, which after patterning remain aspermanent dielectric materials within the semiconductor structure. Themethod of the present invention is useful in forming semiconductorinterconnect structures in which the patternable low-k materials afterpatterning and curing become permanent elements, e.g., patternedinterlayer low-k materials, of the interconnect structure. The inventionaccomplishes this without the need of utilizing separate photoresists.

In a first aspect of the invention, a method of forming a doublepatterned semiconductor structure is provided. The method generallyincludes forming a first patternable low-k material above a surface of amaterial stack. The first patternable low-k material is then patternedto provide a first structure having a first patterned low-k materialabove the surface of the material stack. A second patternable low-kmaterial is formed over the first structure. The second patternablelow-k material is then patterned to provide a second structure includinga second patterned low-k material adjacent to, but not abutting thefirst patterned low-k dielectric material. The first and the secondpatterned low-k materials are cured to form a permanent element of asemiconductor chip. The patterns provided by the first and secondpatterned low-k materials can be optionally transferred into thematerial stack.

In one embodiment of the present invention, the material stack includesat least an inorganic antireflective coating and optionally a dielectriccap. The antireflective coating typically undergoes a post depositiontreatment selected from heat treatment, irradiation of electromagneticwave (such of ultra-violet light), particle beam (such as an electronbeam, or an ion beam), plasma treatment, chemical treatment through agas phase or a liquid phase (such as application of a monolayer ofsurface modifier) or any combination thereof.

In another embodiment of the present invention, the inorganicantireflective coating is formed by vapor deposition and includeselements of M, C and H, wherein M is at least one of the elements of Si,Ge, B, Sn, Fe, Ta, Ti, Ni, Hf and La and, optionally, one of theelements of O, N, S and F.

In a further embodiment of the present invention, the inorganicantireflective coating is formed by liquid deposition and comprises apolymer that has at least one monomer unit having the formula M-R^(A),wherein M is at least one of the elements of Si, Ge, B, Sn, Fe, Ta, Ti,Ni, Hf and La and, optionally, one of the elements of O, N, S and F, andR^(A) is a chromophore.

In an even further embodiment of the present invention, the polymer ofthe liquid deposited antireflective coating further includes anothermonomer unit having the formula M′-R^(B), wherein M′ is at least one ofthe elements of Si, Ge, B, Sn, Fe, Ta, Ti, Ni, Hf and La and,optionally, one of the elements of O, N, S and F, and R^(B) is across-linking agent. In this embodiment, at least one of M and M′ isfurther bonded to an organic ligand of elements of C and H, across-linking component, a chromophore or mixtures thereof.

The first and second patternable low-k materials mentioned above are thesame or different dielectric materials and are positive or negative-toneirradiation/acid sensitive materials comprising a polymer, a copolymer,a blend including at least two of any combination of polymers and/orcopolymers. The polymers include one monomer and the copolymers includeat least two monomers and the monomers of the polymers and the monomersof the copolymers are selected from a siloxane, silane, carbosilane,oxycarbosilane, silsesquioxane, alkyltrialkoxysilane,tetra-alkoxysilane, unsaturated alkyl substituted silsesquioxane,unsaturated alkyl substituted siloxane, unsaturated alkyl substitutedsilane, an unsaturated alkyl substituted carbosilane, unsaturated alkylsubstituted oxycarbosilane, carbosilane substituted silsesquioxane,carbosilane substituted siloxane, carbosilane substituted silane,carbosilane substituted carbosilane, carbosilane substitutedoxycarbosilane, oxycarbosilane substituted silsesquioxane,oxycarbosilane substituted siloxane, oxycarbosilane substituted silane,oxycarbosilane substituted carbosilane, and oxycarbosilane substitutedoxycarbosilane.

In yet still a further embodiment of the invention, at least one of thefirst and/or second patternable low-k materials further comprises afunctionalized sacrificial pore generator which can be removed duringsubsequent processes forming a porous low-k material.

As mentioned above, a curing step is performed that cures at least thesecond patterned low-k material. In some instances, this curing stepalso cures the first patterned low-k material. In yet anotherembodiment, the first patterned low-k material is cured prior to formingthe second patternable low-k dielectric. Notwithstanding which of theseembodiments is performed, curing comprises a thermal cure, an electronbeam cure, an UV cure, an ion beam cure, a plasma cure, a microwave cureor any combination thereof.

In some embodiments, small features that are permanent part of asemiconductor device are formed wherein the small features are formed byrepeating the second patterning step mentioned above at least one moretime.

In a second aspect of the present invention, a method of forming adouble patterned semiconductor structure is provided. The aspectincludes forming a first patternable low-k material on a surface of aninorganic antireflective coating. The first patternable low-k materialis then patterned and cured to provide a first structure having a firstpatterned and cured low-k material on the surface of the inorganicantireflective coating. A second patternable low-k material is formedover the first structure and then the second patternable low-k materialis patterned to provide a second structure including a second patternedlow-k material adjacent to, but not abutting the first patterned andcured low-k material. The second patterned low-k material is cured.Optionally, the patterns provided by the first and second patterned andcured low-k materials are transferred into the inorganic antireflectivecoating.

Many of the embodiments mentioned above for the first aspect of thepresent invention are also applicable herein for the second aspect ofthe invention as well.

In a third aspect of the present invention, a double patternedsemiconductor structure is provided that comprises a first patterned andcured low-k material located on a portion of an antireflective coating;and a second patterned and cured low-k material located on anotherportion of the antireflective coating, wherein the second patterned andcured low-k dielectric material is adjacent to, but not abutting thefirst patterned and cured low-k material, wherein the inorganicantireflective coating is (i) a material having elements of M, C and H,wherein M is at least one of the elements of Si, Ge, B, Sn, Fe, Ta, Ti,Ni, Hf and La, or (ii) a polymer that has at least one monomer unithaving the formula M-R^(A), wherein M is at least one of the elements ofSi, Ge, B, Sn, Fe, Ta, Ti, Ni, Hf and La, and R^(A) is a chromophore.

In one embodiment of the invention, the inorganic antireflective coatingis a polymer which further includes another monomer unit having theformula M′-R^(B), wherein M′ is at least one of the elements of Si, Ge,B, Sn, Fe, Ta, Ti, Ni, Hf and La and, optionally, one of the elements ofO, N, S and F, and R^(B) is a cross-linking agent. In this embodiment ofthe invention, at least one of M and M′ is further bonded to an organicligand of C and H, a cross-linking component, a chromophore or mixturesthereof.

The first and second cured and patternable low-k materials mentionedabove are the same or different dielectric materials and are positive-or negative-tone irradiation/acid sensitive materials comprising apolymer, a copolymer, a blend including at least two of any combinationof polymers and/or copolymers, wherein said polymers include one monomerand said copolymers include at least two monomers and wherein themonomers of the polymers and the monomers of the copolymers are selectedfrom a siloxane, silane, carbosilane, oxycarbosilane, silsesquioxane,alkyltrialkoxysilane, tetra-alkoxysilane, unsaturated alkyl substitutedsilsesquioxane, unsaturated alkyl substituted siloxane, unsaturatedalkyl substituted silane, an unsaturated alkyl substituted carbosilane,unsaturated alkyl substituted oxycarbosilane, carbosilane substitutedsilsesquioxane, carbosilane substituted siloxane, carbosilanesubstituted silane, carbosilane substituted carbosilane, carbosilanesubstituted oxycarbosilane, oxycarbosilane substituted silsesquioxane,oxycarbosilane substituted siloxane, oxycarbosilane substituted silane,oxycarbosilane substituted carbosilane, and oxycarbosilane substitutedoxycarbosilane.

In yet another embodiment of the invention, at least one of the firstand second cured and patterned low-k materials is porous.

In a further embodiment of the present invention, the first and secondcured and patterned low-k materials have a dielectric constant of notmore than 4.3.

In an even further embodiment, the first and second cured and patternedlow-k materials are separated by a distance of roughly half of thedistance of similar features formed by a single exposure patterning.

The present invention offers several advantages: it provides asimplified method to achieve high-resolution patterns for semiconductordevices; it also offers a cost-effective way to generate fine patterneddielectric structures that are permanent parts of a semiconductor chip.In some embodiments of the invention, and when ananti-reflective-coating is used, the anti-reflective-coating and thepatternable low-k material are part of a permanent dielectric materialstack of the interconnect structure.

In addition to the methods described above, the present invention alsorelates to interconnect structures which include the patternable low-kmaterial in a cured state; in the cured state the patternable low-kmaterial serves as the permanent interconnect dielectric in which aconductive material is embedded therein.

DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIGS. 1A-1H are pictorial representations (through cross sectionalviews) depicting basic processing steps that are employed in the presentinvention to provide a multiple patterned structure on a semiconductorchip.

DETAILED DESCRIPTION

The present invention, which provides methods to pattern very smallfeatures into semiconductor structures and the resultant patternedstructures that are formed by such methods, will now be described ingreater detail by referring to the following discussion and drawingsthat accompany the present application. It is noted that the drawingsthat accompany the present application are provided for illustrativepurposes only, and, as such, these drawings are not drawn to scale.

In the following description, numerous specific details are set forth,such as particular structures, components, materials, dimensions,processing steps and techniques, in order to provide a thoroughunderstanding of the present invention. However, it will be appreciatedby one of ordinary skill in the art that the invention may be practicedwithout these specific details. In other instances, well-knownstructures or processing steps have not been described in detail inorder to avoid obscuring the invention.

It is noted that the patternable low-k materials employed in theinvention are any dielectric materials possessing two functions. Theyact as a photoresist during a patterning process and are subsequentlyconverted into a low-k dielectric insulator during a post patterningcure process. The cured product of a patternable low-k material,therefore, can serve as an on-chip dielectric insulator. The patternablelow-k material can be deposited from a liquid phase. In the presentinvention, the terms “cure” or “curing” are used interchangeable torefer one of the processes selected from a thermal cure, an electronbeam cure, an ultra-violet (UV) cure, an ion beam cure, a plasma cure, amicrowave cure or a combination thereof. A “cured” product of apatternable low-k material is the product of the patternable low-kmaterial after it has undergone one of the aforementioned cureprocesses. The “cured” product of a patternable low-k material isdifferent from the patternable low-k material in chemical nature andphysical, mechanical and electrical properties.

The present invention will now be described in reference to FIGS. 1A-1Hwhich illustrate a preferred embodiment of the present invention inwhich a double patterned permanent dielectric structure on asemiconductor chip is formed.

FIG. 1A illustrates an initial structure 10 that is utilized in thisembodiment. The initial structure 10 includes a substrate 12, anoptional dielectric cap 14 located on a surface of substrate 12, and aninorganic antireflective coating 16 located on a surface of the optionaldielectric cap 14. If the optional dielectric cap 14 is not present theinorganic antireflective coating 16 is located directly on a surface ofsubstrate 12.

The substrate 12 may comprise a semiconducting material, an insulatingmaterial, a conductive material, devices or structures made of thesematerials or any combination thereof (e.g., a lower level of aninterconnect structure). When the substrate 12 is comprised of asemiconducting material, any semiconductor such as Si, SiGe, SiGeC, SiC,Ge alloys, GaAs, InAs, InP and other III/V or II/VI compoundsemiconductors, or organic semiconductors may be used. In addition tothese listed types of semiconducting materials, the present inventionalso contemplates cases in which the semiconductor substrate is alayered semiconductor such as, for example, Si/SiGe, Si/SiC,silicon-on-insulators (SOIs) or silicon germanium-on-insulators (SGOIs).These semiconductor materials may form a device, or devices orstructures. These devices or structures may be discrete orinterconnected. These devices and structures may be for logicapplications or memory applications.

When the substrate 12 is an electrically insulating material, theinsulating material can be an organic insulator, an inorganic insulatoror a combination thereof including multilayers. The substrate 12 mayalso include a patternable low-k material as well. These electricallyinsulating materials may be part of a device, or devices or structures.These devices or structures may be discrete or interconnected, Thesedevices and structures may be for logic applications or memoryapplications. When the substrate 12 is an electrically conductingmaterial, the substrate may include, for example, polySi, an elementalmetal, an alloy including at least one elemental metal, a metalsilicide, a metal nitride or a combination thereof includingmultilayers. When the substrate 12 comprises a semiconducting material,one or more semiconductor devices such as, for example, complementarymetal oxide semiconductor (CMOS) devices, strained silicon devices,carbon-based (carbon nanotubes and/or graphene) devices, magnetic spindevices, single electron transistors, quantum devices, molecule-basedswitches and other switching devices that can be part of an integratedcircuit, can be fabricated thereon.

The optional dielectric cap 14 is formed directly on the surface ofsubstrate 12 utilizing a conventional deposition process such as, forexample, chemical vapor deposition (CVD), plasma enhanced chemical vapordeposition (PECVD), atomic layer deposition (ALD), chemical solutiondeposition, or evaporation. The dielectric cap 14 comprises any suitabledielectric capping material such as, for example, SiC, SiN, SiO₂, acarbon doped oxide, a nitrogen and hydrogen doped silicon carbideSiC(N,H) or multilayers thereof. The dielectric cap 14 can be acontinuous layer or a discontinuous layer. The dielectric cap 14 can bea layer with graded composition in the vertical direction. It can alsobe a select cap, such as CoWP.

A post deposition treatment may be applied to the dielectric cap 14 tomodify the properties of either the entire layer or the surface of thedielectric cap layer. This post deposition treatment can be selectedfrom heat treatment, irradiation of electromagnetic wave (such ofultra-violet light), particle beam (such as an electron beam, or an ionbeam), plasma treatment, chemical treatment through a gas phase or aliquid phase (such as application of a monolayer of surface modifier) orany combination thereof. This post-deposition treatment can be blanketor pattern-wise. The purpose of the post deposition treatment is toenhance the chemical, physical, electrical, and/or mechanical propertiesof the dielectric cap, such as adhesion strength. The chemicalproperties include nature and/or location of surface functional groups,and hydrophilicity. The physical properties include density, moistureabsorption, and heat conductivity. The mechanical properties includemodulus, hardness, cohesive strength, toughness, resistance to crack andadhesion strength to its neighboring layers. The electrical propertiesinclude dielectric constant, electrical breakdown field, and leakagecurrent.

The heat treatment should be no high than the temperature that theunderlying substrate can withstand, usually 500° C. This heat treatmentcan be conducted in an inert environment or within a chemicalenvironment in a gas phase or a liquid phase. This treatment step may ormay not be performed in the same tool as that used in forming thedielectric cap 14.

The post deposition treatment by irradiation of electromagnetic wave canbe by ultra-violet (UV) light, microwave and the like. The UV light canbe broadband with a wavelength range from 100 nm to 1000 nm. It can alsobe UV light generated by an excimer laser or other UV light source. TheUV treatment dose can be a few mJ/cm² to thousands of J/cm². Thisirradiation treatment can be conducted at ambient temperature or at anelevated temperature no higher than 500° C. This irradiation treatmentcan be conducted in an inert environment or within a chemicalenvironment in a gas phase or a liquid phase. The following conditionscan be employed for this aspect of the present invention: a radiationtime from 10 sec to 30 mm, a temperature from room temperature to 500°C., and an environment including vacuum, or gases such as, for example,inert gas, N₂, H₂, O₂, NH₃, hydrocarbon, and SiH₄. This treatment stepmay or may not be performed in the same tool as that used in forming thedielectric cap 14.

The post deposition treatment by plasma treatment can be selected fromoxidizing plasma, reducing plasma or a neutral plasma. Oxidizing plasmasinclude, for example, O₂, CO, and CO₂. Reducing plasmas include, forexample, H₂, N₂, NH₃, and SiH₄. The neutral plasmas include, forexample, Ar and He. A plasma treatment time from 1 sec to 10 min and aplasma treatment temperature from room temperature to 400° C. can beemployed. This treatment step may or may not be performed in the sametool as that used in forming the dielectric cap 14.

The post deposition chemical treatment may be conducted in a gas phaseor a liquid phase. The following conditions may be employed for thisaspect of the present invention: a treatment time from 1 sec to 30 min,a temperature from room temperature (i.e., from 20° C. to 30° C.) to500° C. Chemicals suitable for this chemical treatment may be selectedfrom any chemicals that improve chemical, physical, electrical, and/ormechanical properties of the dielectric cap layer, such as adhesionstrength. This chemical treatment may penetrate the entire dielectriccap 14 or is limited only to the surface of the dielectric cap 14.Example chemicals include adhesion promoters such as silanes, siloxanesand silylation agents. This treatment step may or may not be performedin the same tool as that used in forming the dielectric cap 14.

The thickness of the dielectric cap 14 may vary depending on thetechnique used to form the same as well as the material make-up of thelayer. Typically, the dielectric cap 14 has a thickness from 5 nm to 55nm, with a thickness from 20 nm to 45 nm being more typical.

An inorganic antireflective coating (ARC) 16 is formed on a surface ofthe optional dielectric cap 14 if present, or directly on a surface ofthe substrate 12 when the dielectric cap 14 is not present. The ARC 16employed has all of the following general characteristics: (i) It actsas an ARC during a lithographic patterning process; (ii) It withstandshigh-temperature BEOL integration processing (up to 500° C.); (iii) Itprevents resist (e.g., the patternable low-k material) poisoning by thesubstrate; (iv) It provides vertical wall profile and sufficient etchselectivity between the patternable low-k material and the ARC layer;(v) It serves as a permanent dielectric layer in a chip (low dielectricconstant, preferably k<5, more preferably k<3.6); and (vi) It iscompatible with conventional BEOL integration and produces reliablehardware. Further discussion is now provided for characteristics(i)-(v).

Characteristic (i), i.e., ARC 16 acts as an antireflective coating (ARC)during a lithographic patterning process: The ARC may be designed tocontrol reflection of light that is transmitted through the patternablelow-k material (to be subsequently formed), reflected off the substrateand back into the patternable low-k material, where it can interferewith incoming light and cause the patternable low-k material to beunevenly exposed (along the vertical direction). The optical constant ofthe ARC is defined here as the index of refraction n and the extinctioncoefficient k. In general, ARC 16 can be modeled so as to find optimumoptical parameters (n and k values) of the ARC as well as optimumthickness. The preferred optical constants of ARC 16 are in the rangefrom n=1.2 to n=3.0 and k=0.01 to k=0.9, preferably n=1.4 to n=2.6 andk=0.02 to k=0.78 at a Wavelength of 365, 248, 193 and 157, 126 nm andextreme ultraviolet (13.4 nm) radiation. The optical properties andthickness of ARC 16 are optimized to obtain optimal resolution andprofile control of the patternable low-k material during the subsequentpatterning steps, which is well known to those ordinarily skilled in theart.

Characteristic (ii), i.e., ARC 16 can withstand high-temperature BEOLintegration processing (up to 500° C.): ARC 16 must withstand the harshprocessing conditions during BEOL integration. This includes hightemperature and intense UV curing. The process temperature can be ashigh as 450° C. The intensity of the light used in the UV cure processcan be as high as tens of J/cm².

Characteristic (iii), i.e., ARC 16 prevents resist (e.g., patternablelow-k material) poisoning by the substrate: The patternable low-kmaterials employed are preferably chemically amplified resists. They canbe poisoned by any basic contaminant from the underlying substrate, suchas a SiCN dielectric cap. As such, ARC 16 must serve as a barrier layerto prevent basic contaminant from the underlying substrate fromdiffusing into the patternable low-k material to poison the chemicallyamplified patternable low-k material.

Characteristic (iv), i.e., ARC 16 provides vertical wall profile andsufficient etch selectivity between the patternable low-k material andthe ARC layer: ARC 16 should provide sufficient reflectivity controlwith reflectivity from the underlying substrate under a particularlithographic wavelength of less than 8%, preferably less than 5%, morepreferably less than 2% and generate vertical side wafer profile. ARC 16should also generate residue-free patterns with no footing. Moreover,the adhesion of the patternable low-k material should be sufficient toprevent pattern collapse during patterning and a subsequent UV cure. ARC16 should also be designed such that the etch selectivity during ARC/capopen process is sufficiently high so that the opening of the ARC/capstack does not erode significant portion of the patternable low-kmaterial and degrade significantly its pattern profile. An etchselectivity (etch rate ratio of ARC/cap versus patternable low-kmaterial) is greater than 1, preferably greater than 3, more preferablegreater than 5.

Characteristic (v), i.e., ARC 16 serves as a permanent dielectric layerin a chip: ARC 16 remains after patterning and cure of the patternablelow-k material. It serves as a permanent dielectric layer in a chip.Therefore, ARC 16 (after cure) must meet the requirements of an on-chipdielectric insulator, including electrical properties (low dielectricconstant: k less than 5, and preferably k less than 3.6; dielectricbreakdown field: greater than 2 MV/cm, preferably greater than 4 MV/cm,and more preferably greater than 6 MV/cm, leakage: less than 10⁻⁵ A/cm²,preferably less than 10⁻⁷ A/cm², and more preferably less than 10⁻⁹A/cm²); mechanical properties (adhesion energy is equal to or greaterthan the cohesive energy of the weakest layer of the integrated filmstack); must pass electrical and mechanical reliability tests.

The thickness of the ARC 16 may vary depending on the technique used toform the same as well as the material make-up of the layer. If thedielectric constant of the ARC 16 is greater than that of the curedpatternable low-k material, it is preferred that the ARC 16 is thethinnest one that satisfies all the requirements. Typically, the ARC 16has a thickness from 5 nm to 200 nm, with a thickness from 20 nm to 140nm being more typical. The antireflective coating 16 may be inorganic ora hybrid of inorganic and organic.

Inorganic antireflective coatings, such as silicon oxynitride (SiON),silicon carbide (SiC), silicon oxycarbide (SiOC), SiCOH, siloxane,silane, carbosilane, oxycarbosilane, and silsesquioxane, either as apolymer or a copolymer may be employed as ARC 16 and may be deposited,for example, by plasma-enhanced chemical vapor deposition, spin-ontechniques, spray coating, dip coating, etc. ARC 16 may be a singlelayer or multilayer. When ARC 16 is a multilayer ARC, the deposition ofeach layer may be the same or a combination of deposition methods can beused. The chemical composition of ARC 16 may be uniform or graded alongthe vertical direction. After applying ARC 16, particularly those from aliquid phase, a post deposition baking step is usually required toremove unwanted components, such as solvent, and to effect crosslinking.The post deposition baking step of ARC 16 is typically, but notnecessarily always, performed at a temperature from 80° C. to 300° C.,with a baking temperature from 120° C. to 200° C. being even moretypical.

In some embodiments, the as-deposited ARC 16 may be subjected to a postdeposition treatment to improve the properties of the entire layer orthe surface of the ARC 16. This post deposition treatment can beselected from heat treatment, irradiation of electromagnetic wave (suchas ultra-violet light), particle beam (such as an electron beam, or anion beam), plasma treatment, chemical treatment through a gas phase or aliquid phase (such as application of a monolayer of surface modifier) orany combination thereof. This post-deposition treatment can be blanketor pattern-wise. The purpose of this post deposition treatment is toenhance the chemical, physical, electrical, and/or mechanical propertiesof the ARC 16 and/or the film stack, such as adhesion strength. Thechemical properties include nature and/or location of surface functionalgroups, and hydrophilicity. The physical properties include density,moisture absorption, and heat conductivity. The mechanical propertiesinclude modulus, hardness, cohesive strength, toughness, resistance tocrack and adhesion strength to its neighboring layers. The electricalproperties include dielectric constant, electrical breakdown field, andleakage current.

The conditions of the post treatments used here for ARC 16 are the sameas those described above for the optional dielectric cap 14

In one embodiment, the ARC 16 that is employed is an inorganiccomposition that includes elements of M, C (carbon) and H (hydrogen),wherein M is selected from at least one of the elements of Si, Ge, B,Sn, Fe, Ta, Ti, Ni, Hf and La. Such an ARC is described for examplewithin U.S. Ser. No. 11/858,636, filed Sep. 20, 2007, now U.S. PatentPublication No. 2009/0079076 the entire content of which is incorporatedherein by reference. This inorganic ARC may optionally include elementsof O, N, S, F or mixtures thereof. In some embodiments, M is preferablySi. In some embodiments, the ARC composition may also be referred to asa vapor deposited M:C:H: optionally X material, wherein M is as definedabove, and X is at least one element of O, N, S and F.

In such an embodiment, ARC 16 is produced by a vapor or liquid phasedeposition (such as, for example, CVD, PECVD, PVD, ALD and spin-oncoating) method using appropriate Si, Ge, B, Sn, Fe, Ta, Ti, Ni, Hf andLa precursors by adjusting process parameters and/or precursorcomposition.

In a preferred embodiment, ARC 16 is a Si:C:H:X film. These Sicontaining films are deposited from at least one Si containingprecursor. More particularly, the Si:C:H:X films are deposited from atleast one Si containing precursor with, or without, additions ofnitrogen and/or oxygen and/or fluorine and/or sulfur containingprecursors. The Si containing precursor that is employed can compriseany Si containing compound including molecules selected from silane(SiH₄) derivatives having the molecular formulas SiR₄, cyclic Sicontaining compounds including cyclocarbosilane where the Rsubstitutents may or may not be identical and are selected from H,alkyl, phenyl, vinyl, allyl, alkenyl or alkynyl groups that may belinear, branched, cyclic, polycyclic and may be functionalized withnitrogen containing substituents, any cyclic Si containing compoundsincluding cyclosilanes, and cyclocarbosilanes.

Preferred Si precursors include, but are not limited to silane,methylsilane, dimethylsilane, trimethysilane, tetramethylsilane,ethylsilane, diethylsilane, triethylsilane, tetraethylsilane,ethylmethylsilane, triethylmethylsilane, ethyldimethylsilane,ethyltrimethylsilane, diethyldimethylsilane,1,1,3,3,-tetrahydrido-1,3-disilacyclobutane; 1,3-disilacyclobutane;1,3-dimethyl-1,3-dihydrido-1,3-disilylcyclobutane; 1,1,3,3,tetramethyl-1,3-disilacyclobutane;1,1,3,3,5,5-hexahydrido-1,3,5-trisilane;1,1,3,3,5,5-hexamethyl-1,3,5-trisilane;1,1,1,4,4,4,-hexahydrido-1,4-disilabutane; and 1,4-bis-trihydrosilylbenzene. Also the corresponding meta substituted isomers, such asdimethyl-1-propyl-3-silabutane; 2-silapropane, 1,3-disilacyclobutane,1,3-disilapropane, 1,5-disilapentane, or 1,4-bis-trihydrosilyl benzenecan be employed.

A single precursor such as silane amine, Si(Net)₄, can be used as thesilicon, carbon and nitrogen source. Another preferred method is amixture of precursors, a Si containing source such as silane, disilane,or a alkylsilane such as tetramethylsilane, or trimethylsilane, and anitrogen containing source such as ammonia, amines, nitriles, aminos,azidos, azos, hydrizos. An additional carbon source and/or carbon andnitrogen containing source comprised of a linear, branched, cyclic orpolycyclic hydrocarbon backbone of —[CH₂]_(n)—, where n is greater thanor equal to 1, and may be substituted by functional groups selected fromalkenes (—C═C—), alkynes (—C≡C—), amines (—C—N—), nitriles (—C≡N), amino(—NH₂), azido (—N═N═N—) and azo (—N═N—) may also be required. Thehydrocarbon backbone may be linear, branched, or cyclic and may includea mixture of linear branched and cyclic hydrocarbon moieties. Theseorganic groups are well known and have standard definitions that arealso well known in the art. These organic groups can be present in anyorganic compound.

In some embodiments, the method may further include the step ofproviding a parallel plate reactor, which has an area of a substratechuck from 85 cm² to 750 cm², and a gap between the substrate and a topelectrode from 1 cm to 12 cm. A high frequency RF power is applied toone of the electrodes at a frequency from 0.45 MHz to 200 MHz.Optionally, an additional RF power of lower frequency than the first RFpower can be applied to one of the electrodes. A single source precursoror a mixture of precursors which provide a silicon, carbon and nitrogensource are introduced into a reactor.

The conditions used for the deposition step may vary depending on thedesired final properties of ARC 16. Broadly, the conditions used forproviding the ARC 16 comprising elements of Si:C:H:X, include: settingthe substrate temperature within a range from 100° C. to 700° C.;setting the high frequency RF power density within a range from 0.1W/cm² to 2.0 W/cm²; setting the gas flow rates within a range from 5sccm to 10000 sccm, setting the inert carrier gases, such as helium(or/and argon) flow rate within a range from 10 sccm to 10000 sccm;setting the reactor pressure within a range from 1 Torr to 10 Torr; andsetting the high frequency RF power within a range from 10 W to 1000 W.Optionally, a lower frequency power may be added to the plasma within arange from 10 W to 600 W. When the conductive area of the substratechuck is changed by a factor of X, the RF power applied to the substratechuck is also changed by a factor of X. Gas flows of silane, carbonand/or nitrogen gas precursors are flowed into the reactor at a flowrate within a range from 11 sccm to 1000 sccm. While gas precursors areused in the above example, liquid precursors may also be used for thedeposition.

Other precursors are also contemplated besides methylsilanes. Typically,any precursor including elements of M, C and H can be used. That is, anyprecursor including M and at least one organic ligand can be used.Examples include methylsilanes such as trimethylsilane ortetramethylsilane, siloxanes such as tetramethylcylcotetrasiloxane oroctylmethylcyelotetrasiloxane, or methyl gemanes such astrimethylgermane or tetraethylgermane.

Organic precursors may also be used in addition to the organometallicones as long as the resultant ARC film possesses the desirableattributes described above. These organic precursors are selected fromhydrocarbons and their derivatives, including linear, branched, and ringtype molecules.

The atomic % ranges for M in such ARC materials are as follows:preferably 0.1 atomic % to 95 atomic %, more preferably 0.5 atomic % to95 atomic %, most preferably 1 atomic % to 60 atomic % and most highlypreferably 5 atomic % to 50 atomic %. The atomic % ranges for C in ARC16 are as follows: preferably 0.1 atomic % to 95 atomic %, morepreferably 0.5 atomic % to 95 atomic %, most preferably 1 atomic % to 60atomic % and most highly preferably 5 atomic % to 50 atomic %. Theatomic % ranges for H in ARC 16 are as follows: preferably 0.1 atomic %to 50 atomic %, more preferably 0.5 atomic % to 50 atomic %, mostpreferably 1 atomic % to 40 atomic % and most highly preferably 5 atomic% to 30 atomic %. The atomic % ranges for X in ARC 16 are as follows:preferably O atomic % to 70 atomic %, more preferably 0.5 atomic % to 70atomic %, most preferably 1 atomic % to 40 atomic % and most highlypreferably 5 atomic % to 30 atomic %.

The ARC 16 including elements of M, C and H has a tunable index ofrefraction and extinction coefficient which can be optionally gradedalong the film thickness to match the optical properties of thesubstrate and the patternable low-k material. The optical properties andthe lithographic features of ARC 16 are vastly superior to thoseobtained by the prior art.

The following are a list of non-limiting exemplary embodiments in whichthe ARC containing elements of M, C and H is deposited on a substratethat is positioned on a powered electrode and therefore a negative biasis required: In one embodiment, a Si:C:H film is deposited under thefollowing conditions: precursor-tetramethylsilane at a flow of 10 sccm,pressure in reactor=200 mtorr, substrate temperature=60° C., substratebias-1-200 V. In a second embodiment, a Si:C:O:H film is deposited underthe following conditions: precursor=tetramethylsilane at a flow of 10sccm mixed with oxygen at a flow of 2 sccm, pressure in reactor=200mtorr, substrate temperature=180° C., substrate bias=−200 V. In a thirdembodiment, a Si:C:H film is deposited under the following conditions:precursor-trimethylsilane at a flow of 10 sccm, pressure in reactor=200mtorr, substrate temperature=60° C., substrate bias=−200 V. In a fourthembodiment, a Si:C:O:H film is deposited under the following conditions:precursor-trimethylsilane at a flow of 10 sccm mixed with oxygen at aflow of 2 sccm, pressure in reactor=200 mtorr, substrate temperature=60°C., substrate bias=−200 V. In a fifth embodiment, a Si:C:O:H film isdeposited under the following conditions:precursor=tetramethyltetrasiloxane with argon as a carrier gas at flowof 30 sccm, pressure in reactor=250 mtorr, substrate temperature=60° C.,substrate bias=−150 V. In a sixth embodiment, a Si:C:O:H film isdeposited under the following conditions:precursor=tetramethyltetrasiloxane with argon as a carrier gas at flowof 30 sccm, pressure in reactor=−250 mtorr, substrate temperature=180°C., substrate bias=−200 V. In a seventh embodiment, a Si:C:O:H film isdeposited under the following conditions:precursor=tetramethyltetrasiloxane with argon as a carrier gas at flowof 30 sccm, pressure in reactor=200 mtorr, substrate temperature=180°C., substrate bias=−200 V. In an eighth embodiment, a Ge:C:H film isdeposited under the following conditions: precursor=tetramethylgermanewith argon as a carrier gas at flow of 30 sccm, pressure in reactor=50mtorr, substrate temperature=180° C., substrate bias=−250 V. In a ninthembodiment, a Ge:C:H film is deposited under the following conditions:precursor-tetramethylgermane with argon as a carrier gas at flow of 30sccm, pressure in reactor=100 mtorr, substrate temperature=60° C.,substrate bias=−50 V. In a tenth embodiment, a Ge:C:H:O film isdeposited under the following conditions: precursor=tetramethylgermaneat a flow of 15 sccm mixed with oxygen at a flow of 2 sccm, pressure inreactor=200 mtorr, substrate temperature=60° C., substrate bias=−50 V.

The ARC 16 including elements of M, C and H can be deposited also in aparallel plate PECVD reactor with the substrate positioned on thegrounded electrode. It can be deposited in conditions similar to thosedescribed in the previous examples but at substrate temperatures up to400° C., and in high-density plasma type reactors under suitable chosenconditions. It should be noted that by changing process parameters suchas bias voltage, gas mixture, gas flow, pressure and depositiontemperature, the film's optical constants can be changed. In addition,the composition of the starting precursor as well as the introduction ofoxygen, nitrogen, fluorine, and sulfur containing precursors also allowsthe tunability of these films. The ARC's optical constants are definedhere as the index of refraction n and the extinction coefficient k.

In another embodiment, the ARC 16 that is employed is formed by a liquiddeposition process including for example, spin-on coating, spraycoating, dip coating, brush coating, evaporation or chemical solutiondeposition. This ARC formed by liquid deposition comprises a polymerthat has at least one monomer unit comprising the formula M-R^(A)wherein M is at least one of the elements of Si, Ge, B, Sn, Fe, Ta, Ti,Ni, Hf and La and R^(A) is a chromophore. Such an ARC is described inU.S. Ser. No. 11/858,615, filed Sep. 20, 2007, now U.S. PatentPublication No. 2009/0081418 the entire content of which is incorporatedherein by reference. In some embodiments, M within the monomer unit mayalso be bonded to organic ligands including elements of C and H, across-linking component, another chromophore or mixtures thereof. Theorganic ligands may farther include one of the elements of O, N, S andF. When the organic ligand is bonded to M, it is bonded to M′ through C,O, N, S, or F.

In other embodiments, the ARC 16 formed by liquid deposition may alsoinclude at least one second monomer unit, in addition to the at leastone monomer unit represented by the formula M-R^(A). When present, theat least one second monomer unit has the formula M-R^(B), wherein M′ isat least one of the elements of Si, Ge, B, Sn, Fe, Ta, Ti, Ni, Hf andLa, and R^(B) is a cross-linking agent. M and M′ may be the same ordifferent elements. In these two formulae, M and M′ within the monomerunit may be also be bonded to organic ligands including atoms of C andH, a cross-linking component, a chromophore or mixtures thereof. Theorganic ligands may further include one of the elements of O, N, S andF. When the organic ligand is bonded to M and M′, it is bonded to M orM′ through C, O, N, S, or F.

The liquid ARC composition comprising M-R^(A) or M-R^(A) and M′-R^(B)may also comprise at least one additional component, including aseparate crosslinker, an acid generator or a solvent.

When liquid deposition is employed, the ARC 16 is formed by liquid phasedeposition of a liquid composition that includes an inorganic precursorthat includes element of M, C and H, wherein M is at least one of theelements of Si, Ge, B, Sn, Fe, Ta, Ti, Ni, Hf and La. The inorganicprecursor used in forming the ARC may optionally include elements of O,N, S, F or mixtures thereof. In some embodiments, M is preferably Si.The liquid composition also includes, in addition to the inorganicprecursor, a chromophore, a cross-linking component, an acid generatorand solvent.

One embodiment of the inorganic ARC 16 composition used in the liquiddeposition embodiment comprises M-R^(A) and M′-R^(B) units, wherein Mand M′ is at least one of the elements of Si, Ge, B, Sn, Fe, Ta, Ti, Ni,Hf and La or is selected from Group IIIB to Group VIB, Group IIIA, andGroup IVA. The inorganic precursor used in forming the ARC mayoptionally include elements of O, N, S, F or mixtures thereof. Oneembodiment of the ARC composition comprises the MO_(y) unit which can beany one of many different metal-oxide forms. An exemplary list of suchmetal-oxide forms for a particular metal is as follows: MO₃; wherein Mis Sc, Y, lanthanide, and Group IIIA; B, Al, Ga or In; MO₄; wherein M isGroup IVB; Ti, Zr or Hf, and Group IVA; Sn or Ge; MO₅; wherein M isGroup VB; V, Nb or Ta; or P. The Group VB metals are also known to formstable metal oxo forms, LMO₃, wherein L is an oxo; LMO; many of thelisted metals form stable acetoacetato-metal complexes; LMO; many of thelisted metals form stable cyclopentadienyl-metal complexes; LMO; whereinL is an alkoxy ligand; M is Sc, Y, or lanthanide, Group IVB, and GroupVB; or LMO; wherein L is an alkyl or phenyl ligand; M is Group IIIA orGroup IVA.

The chromophore, cross-linking component and acid generator that can beused in the liquid deposited ARC are defined in greater detail withrespect to the following preferred embodiment of the present invention.In a preferred embodiment, the ARC 16 formed by liquid deposition ischaracterized by the presence of a silicon-containing polymer havingunits selected from a siloxane, silane, carbosilane, oxycarbosilane,silsesquioxane, alkyltrialkoxysilane, tetra-alkoxysilane, orsilicon-containing and pendant chromophore moieties. The polymercontaining these units may be a polymer containing these units in thepolymer backbone and/or in pendant groups. Preferably, the polymercontains the preferred units in its backbone. The polymer is preferablya polymer, a copolymer, a blend including at least two of anycombination of polymers and/or copolymers, wherein the polymers includeone monomer and the copolymers include at least two monomers and whereinthe monomers of the polymers and the monomers of the copolymers areselected from a siloxane, silane, carbosilane, oxycarbosilane,silsesquioxane, alkyltrialkoxysilane, tetra-alkoxysilane, unsaturatedalkyl substituted silsesquioxane, unsaturated alkyl substitutedsiloxane, unsaturated alkyl substituted silane, an unsaturated alkylsubstituted carbosilane, unsaturated alkyl substituted oxycarbosilane,carbosilane substituted silsesquioxane, carbosilane substitutedsiloxane, carbosilane substituted silane, carbosilane substitutedcarbosilane, carbosilane substituted oxycarbosilane, oxycarbosilanesubstituted silsesquioxane, oxycarbosilane substituted siloxane,oxycarbosilane substituted silane, oxycarbosilane substitutedcarbosilane, and oxycarbosilane substituted oxycarbosilane.

The polymer should have solution and film-forming characteristicsconducive to forming an ARC by conventional spin-coating. In addition tothe chromophore moieties discussed below, the silicon-containing polymeralso preferably contains a plurality of reactive sites distributed alongthe polymer for reaction with the cross-linking component.

Examples of suitable polymers include polymers having the silsesquioxane(ladder, caged, or network) structure. Such polymers preferably containmonomers having structures (I) and (II) below:

where R^(C) comprises a chromophore and R^(D) comprises a reactive sitefor reaction with the cross-linking component.

Alternatively, general linear organosiloxane polymers containingmonomers (I) and (II) can also be used. In some cases, the polymercontains various combinations of monomers (I) and (II) including linearstructures such that the average structure for R^(C)-containing monomersmay be represented as structure (III) below and the average structurefor R^(D)-containing monomers may be represented by structure (IV)below:

where x is from 1 to 1.5. In theory, x may be greater than 1.5, however,such compositions generally do not possess characteristics suitable forspin-coating processes (e.g., they form undesirable gel or precipitatephases).

Generally, silsesquioxane polymers are preferred. If the ordinaryorganosiloxane polymers are used (e.g., monomers of linear structures(I) and (III)), then preferably, the degree of cross-linking isincreased compared to formulations based on silsesquioxanes.

The chromophore-containing groups R^(C) (or R^(A) in the genericdescription above) may contain any suitable chromophore which (i) can begrafted onto the silicon-containing polymer (or M moiety of the genericmonomer defined above) (ii) has suitable radiation absorptioncharacteristics at the imaging wavelength, and (iii) does not adverselyaffect the performance of the layer or any overlying layers.

Preferred chromophore moieties include benzene and its derivatives,chrysenes, pyrenes, fluoranthrenes, anthrones, benzophenones,thioxanthones, and anthracenes. Anthracene derivatives, such as thosedescribed in U.S. Pat. No. 4,371,605 may also be used; the disclosure ofthis patent is incorporated herein by reference. In one embodiment,phenol, hydroxystyrene, and 9-anthracene methanol are preferredchromophores. The chromophore moiety preferably does not containnitrogen, except for possibly deactivated amino nitrogen such as inphenol thiazine.

The chromophore moieties may be chemically attached by acid-catalyzedO-alkylation or C-alkylation such as by Friedel-Crafts alkylation. Thechromophore moieties may also be chemically attached by hydrosilylationof SiH bond on the parent polymer. Alternatively, the chromophore moietymay be attached by an esterification mechanism. A preferred acid forFriedel-Crafts catalysis is HCl.

Preferably, 15 to 40% of the functional groups contain chromophoremoieties. In some instances, it may be possible to bond the chromophoreto the monomer before formation of the silicon-containing polymer. Thesite for attachment of the chromophore is preferably an aromatic groupsuch as a hydroxybenzyl or hydroxymethylbenzyl group. Alternatively, thechromophore may be attached by reaction with other moieties such ascyclohexanol or other alcohols. The reaction to attach the chromophoreis preferably an esterification of the alcoholic OH group.

R^(D) (or R^(B) in the generic description above) comprises a reactivesite for reaction with a cross-linking component. Preferred reactivemoieties contained in R^(D) are alcohols, more preferably aromaticalcohols (e.g., hydroxybenzyl, phenol, hydroxymethylbenzyl, etc.) orcycloaliphatic alcohols (e.g., cyclohexanoyl). Alternatively, non-cyclicalcohols such as fluorocarbon alcohols, aliphatic alcohols, aminogroups, vinyl ethers, and epoxides may be used.

Preferably, the silicon-containing polymer (before attachment of thechromophore) of a liquid deposited ARC 16 ispoly(4-hydroxybenzylsilsesquioxane). Examples of other silsesquioxanepolymers include: poly(p-hydroxyphenylethylsilsesquioxane),poly(p-hydroxyphenylethylsilsesquioxane-co-p-hydroxy-alpha-methylbenzylsilsesquioxane),poly(p-hydroxyphenylethylsilsesquioxane-co-methoxybenzylsilsesquioxane),poly(p-hydroxyphenylethylsilsesquioxane-co-t-butylsilsesquioxane),poly(p-hydroxyphenylethylsilsesquioxane-co-cyclohexylsilsesquioxane),poly(p-hydroxyphenylethylsilsesquioxane-co-phenylsilsesquioxane),poly(p-hydroxyphenylethylsilsesquioxane-co-bicycloheptylsilsesquioxane),poly(p-hydroxy-alpha-methylbenzylsilsesquioxane),poly(p-hydroxy-alpha-methylbenzylsilsesquioxane-co-p-hydroxybenzylsilsesquioxane),poly(p-hydroxy-alpha-methylbenzylsilsesquioxane-co-methoxybenzylsilsesquioxane),poly(p-hydroxy-alpha-methylbenzylsilsesquioxane-co-t-butylsilsesquioxane),poly(p-hydroxy-alpha-methylbenzylsilsesquioxane-co-cyclohexylsilsesquioxane),poly(p-hydroxy-alpha-methylbenzylsilsesquioxane-co-phenylsilsesquioxane),poly(p-hydroxy-alpha-methylbenzylsilsesquioxane-co-bicycloheptylsilsesquioxane),poly(p-hydroxybenzylsilsesquioxane-co-p-hydroxyphenylethylsilsesquioxane),andpoly(p-hydroxy-alpha-methylbenzylsilsesquioxane-co-alpha-methylbenzylsilsesquioxane).

The Si containing polymers that can be used in a liquid deposited ARC 16preferably have a weight average molecular weight, before reaction withthe cross-linking component, of at least 1000, more preferably a weightaverage molecular weight of 1000-10000.

The cross-linking component of the liquid deposited ARC 16 is preferablya crosslinker that can be reacted with the SiO containing polymer in amanner which is catalyzed by generated acid and/or by heating. Thiscross-linking component can be inorganic or organic in nature. It can bea small compound (as compared with a polymer or copolymer) or a polymer,a copolymer, or a blend including at least two of any combination ofpolymers and/or copolymers, wherein the polymers include one monomer andthe copolymers include at least two monomers. Generally, thecross-linking component used in the liquid deposited antireflectivecompositions may be any suitable cross-linking agent known in thenegative photoresist art which is otherwise compatible with the otherselected components of the composition. The cross-linking agentspreferably act to crosslink the polymer component in the presence of agenerated acid. Preferred cross-linking agents are glycoluril compoundssuch as tetramethoxymethyl glycoluril, methylpropyltetramethoxymethylglycoluril, and methylphenyltetramethoxymethyl glycoluril, availableunder the POWDERLINK trademark from American Cyanamid Company. Otherpossible cross-linking agents include: 2,6-bis(hydroxymethyl)-p-cresol,compounds having the following structures:

including their analogs and derivatives, such as those found in JapaneseLaid-Open Patent Application (Kokai) No. 1-293339, as well as etherifiedamino resins, for example methylated or butylated melamine resins(N-methoxymethyl- or N-butoxymethyl-melamine respectively) ormethylated/butylated glycolurils, for example as can be found inCanadian Patent No. 1 204 547. Other cross-linking agents such asbis-epoxies or bis-phenols (e.g., bisphenol-A) may also be used.Combinations of cross-linking agents may be used. The cross-linkingcomponent may be chemically bonded to the Si containing polymerbackbone.

In another embodiment, the cross-linking component is asilicon-containing polymer having at least one unit selected from asiloxane, silane, carbosilane, oxycarbosilane, silsesquioxane,alkyltrialkoxysilane, and tetra-alkoxysilane. The polymer is preferablya polymer, a copolymer, a blend including at least two of anycombination of polymers and/or copolymers, wherein the polymers includeone monomer and the copolymers include at least two monomers and whereinthe monomers of the polymers and the monomers of the copolymers areselected from a siloxane, silane, carbosilane, oxycarbosilane,silsesquioxane, alkyltrialkoxysilane, tetra-alkoxysilane, unsaturatedalkyl substituted silsesquioxane, unsaturated alkyl substitutedsiloxane, unsaturated alkyl substituted silane, an unsaturated alkylsubstituted carbosilane, unsaturated alkyl substituted oxycarbosilane,carbosilane substituted silsesquioxane, carbosilane substitutedsiloxane, carbosilane substituted silane, carbosilane substitutedcarbosilane, carbosilane substituted oxycarbosilane, oxycarbosilanesubstituted silsesquioxane, oxycarbosilane substituted siloxane,oxycarbosilane substituted silane, oxycarbosilane substitutedcarbosilane, and oxycarbosilane substituted oxycarbosilane.

The acid generator used in the liquid deposited ARC composition ispreferably an acid generator compound that liberates acid upon thermaltreatment. A variety of known thermal acid generators are suitablyemployed such as, for example, 2,4,4,6-tetrabromocyclohexadienone,benzoin tosylate, 2-nitrobenzyl tosylate and other alkyl esters oforganic sulfonic acids, blocked alkyl phosphoric acids, blockedperfluoroalkyl sulfonic acids, alkyl phosphoric acid/amine complexes,perfluoroalkyl acid quats wherein the blocking can be by covalent bonds,amine and quaternary ammonium. Compounds that generate a sulfonic acidupon activation are generally suitable. Other suitable thermallyactivated acid generators are described in U.S. Pat. Nos. 5,886,102 and5,939,236; the disclosures of these two patents are incorporated hereinby reference. If desired, a radiation-sensitive acid generator may beemployed as an alternative to a thermally activated acid generator or incombination with a thermally activated acid generator. Examples ofsuitable radiation-sensitive acid generators are described in U.S. Pat.Nos. 5,886,102 and 5,939,236. Other radiation-sensitive acid generatorsknown in the resist art may also be used as long as they are compatiblewith the other components of the antireflective composition. Where aradiation-sensitive acid generator is used, the cure (cross-linking)temperature of the composition may be reduced by application ofappropriate radiation to induce acid generation which in turn catalyzesthe cross-linking reaction. Even if a radiation-sensitive acid generatoris used, it is preferred to thermally treat the composition toaccelerate the cross-linking process (e.g., for wafers in a productionline).

The antireflective compositions used in the liquid deposition processpreferably contain (on a solids basis) (i) from 10 wt % to 98 wt. % of apolymer including M, more preferably from 70 wt. % to 80 wt. %, (ii)from 1 wt % to 80 wt. % of cross-linking component, more preferably from3 wt. % to 25%, most preferably from 5 wt. % to 25 wt. %, and (iii) from1 wt. % to 20 wt. % acid generator, more preferably 1 wt. % to 15 wt. %.

When ARC 16 is formed by liquid deposition process any liquid depositionprocess including for example, spin-on coating, spray coating, dipcoating, brush coating, evaporation or chemical solution deposition canbe used. After liquid depositing the ARC 16, a post deposition bakingstep is typically, but not necessarily always, used to remove unwantedcomponents, such as solvent, and to effect crosslinking. When performed,the baking step is conducted at a temperature from 60° C. to 400° C.,with a baking temperature from 80° C. to 300° C. being even morepreferred. The duration of the baking step varies and is not critical tothe practice of the present invention. The baked and previously liquiddeposited ARC 16 may further undergo a curing process. The curing isperformed in the present invention by a thermal cure, an electron beamcure, an ultra-violet (UV) cure, an ion beam cure, a plasma cure, amicrowave cure or any combination thereof.

In some embodiments, the as-deposited and cured ARC 16 may be subjectedto a post deposition treatment to improve the properties of the entirelayer or the surface of the ARC 16. This post deposition treatment canbe selected from heat treatment, irradiation of electromagnetic wave(such as ultra-violet light), particle beam (such as an electron beam,or an ion beam), plasma treatment, chemical treatment through a gasphase or a liquid phase (such as application of a monolayer of surfacemodifier) or any combination thereof. The conditions for thesetreatments are similar to the ones mentioned above for the optionaldielectric cap 14.

In addition, the composition of the starting precursor used in liquiddeposition as well as the introduction of oxygen, nitrogen, fluorinecontaining precursors also allows the tunability of these films.

In either embodiment mentioned above, the ARC's optical constants aredefined here as the index of refraction n and the extinction coefficientk. In general, ARC 16 can be modeled so as to find optimum opticalparameters (n and k values) of ARC as well as optimum thickness. Thepreferred optical constants of the ARC 16 are in the range from n=1.4 ton=2.6 and k=0.01 to k=0.78 at a wavelength of 248, 193 and 157, 126 nmand extreme ultraviolet (13.4 nm) radiation.

In addition to the above, ARC 16 in any embodiment does not interactwith the patternable low-k material to induce residue, footing orundercutting. Moreover, ARC 16 has good etch selectivity to thepatternable dielectric material. Etch selectivities of 1.5-4 to 1 of ARC16 to low-k dielectric material can be obtained. Furthermore, the use ofthe ARC 16 of described above (vapor or liquid deposited) maintains thepattern and structural integrity after curing of the patternable low-kmaterial. This is critical as ARC layer 16 is retained as a permanentpart of the final interconnect stack.

Next, and as illustrated in FIG. 1B, a first patternable low-k material18, which combines the function of a photoresist and low-k material intoone single material is provided. As shown, the first patternable low-kmaterial 18 is provided directly on the surface of the ARC 16.

The first patternable low-k material 18 is provided (i.e., formed)utilizing a conventional deposition process including, for example,spin-on-coating, dip coating, brush coating, spray coating, and ink-jetdispensing. After applying the first patternable low-k material 18, apost deposition baking step is typically, but not necessarily always,required to remove unwanted components, such as solvent. When performed,the baking step is conducted at a temperature from 40° C. to 200° C.,with a baking temperature from 60° C. to 140° C. being even morepreferred. The duration of the baking step varies from 10 seconds to 600seconds and is not critical herein.

The thickness of the first patternable low-k material 18 may varydepending on the requirement of the chip and the technique used to formthe same as well as the material make-up of the layer. Typically, thefirst patternable low-k material 18 has a thickness from 1 nm to 50000nm, with a thickness from 20 nm to 5000 nm being more typical.

As stated above, the first patternable low-k material 18 functions as aphotoresist and is converted into a low-k material during postpatterning processing, by heat, UV light, electron beam, ion beam,microwave, plasma cure, thermal cure or a combination thereof. Forinstance, the first patternable low-k material 18 may comprise afunctionalized polymer, copolymer, or a blend including at least two ofany combination of polymers and/or copolymers having one or moreacid-sensitive imageable groups. These polymers, copolymers or blendscan be converted into low-k polymers after subsequent processing. It isnoted that when the patternable low-k material 18 is a polymer, itincludes at least one monomer (to be described in greater detail below).When the patternable low-k material 18 is a copolymer, it includes atleast two monomers (to be described in greater detail below). The blendsof polymers and/or copolymers include at least two of any combination ofpolymers and/or copolymers described below.

In general terms, the patternable low-k material 18 comprises a polymer,a copolymer, or a blend including at least two of any combination ofpolymers and/or copolymers, wherein the polymers include one monomer andthe copolymers include at least two monomers and wherein the monomers ofthe polymers and the monomers of the copolymers are selected from asiloxane, silane, carbosilane, oxycarbosilane, silsesquioxane,alkyltrialkoxysilane, tetra-alkoxysilane, unsaturated alkyl substitutedsilsesquioxane, unsaturated alkyl substituted siloxane, unsaturatedalkyl substituted silane, an unsaturated alkyl substituted carbosilane,unsaturated alkyl substituted oxycarbosilane, carbosilane substitutedsilsesquioxane, carbosilane substituted siloxane, carbosilanesubstituted silane, carbosilane substituted carbosilane, carbosilanesubstituted oxycarbosilane, oxycarbosilane substituted silsesquioxane,oxycarbosilane substituted siloxane, oxycarbosilane substituted silane,oxycarbosilane substituted carbosilane, and oxycarbosilane substitutedoxycarbosilane.

More specifically, the first patternable low-k material 18 comprises aphoto/acid-sensitive polymer of one monomer or a copolymer of at leasttwo monomers selected from siloxane, silane, carbosilane,oxycarbosilane, organosilicates, silsesquioxanes and the like. The firstpatternable low-k material 18 may also comprise a polymer of one monomeror a copolymer of at least two monomers selected fromalkyltrialkoxysilane, tetra-alkoxysilane, unsaturated alkyl (such asvinyl) substituted silsesquioxane, unsaturated alkyl substitutedsiloxane, unsaturated alkyl substituted silane, an unsaturated alkylsubstituted carbosilane, unsaturated alkyl substituted oxycarbosilane,carbosilane substituted silsesquioxane, carbosilane substitutedsiloxane, carbosilane substituted silane, carbosilane substitutedcarbosilane, carbosilane substituted oxycarbosilane, oxycarbosilanesubstituted silsesquioxane, oxycarbosilane substituted siloxane,oxycarbosilane substituted silane, oxycarbosilane substitutedcarbosilane, and oxycarbosilane substituted oxycarbosilane.Additionally, the patternable low-k dielectric material 18 may comprisea blend including at least two of any combination of polymers and/orcopolymers, wherein the polymers include one monomer and the copolymersinclude at least two monomers and wherein the monomers of the polymersand the monomers of the copolymers are selected from a siloxane, silane,carbosilane, oxycarbosilane, silsesquioxane, alkyltrialkoxysilane,tetra-alkoxysilane, unsaturated alkyl substituted silsesquioxane,unsaturated alkyl substituted siloxane, unsaturated alkyl substitutedsilane, an unsaturated alkyl substituted carbosilane, unsaturated alkylsubstituted oxycarbosilane, carbosilane substituted silsesquioxane,carbosilane substituted siloxane, carbosilane substituted silane,carbosilane substituted carbosilane, carbosilane substitutedoxycarbosilane, oxycarbosilane substituted silsesquioxane,oxycarbosilane substituted siloxane, oxycarbosilane substituted silane,oxycarbosilane substituted carbosilane, and oxycarbosilane substitutedoxycarbosilane.

Optionally the first patternable low-k material 18 may comprise at leastone microscopic pore generator (porogen). The pore generator may be ormay not be photo/acid sensitive. By “photo/acid sensitive”, it meansthat this porogen is sensitive to light and/or acid such that theporogen itself is patternable or enhances the resolution and/or thepattern quality of the patternable low-k material. This pore generatorhas these attributes: (1) is compatible with the other components of thepatternable low-k composition, i.e., without phase separation aftercoating and other processing; (2) can be patterned with standardlithographic techniques as part of the patternable low-k composition;and (3) can be removed during the post patterning cure process togenerate microscopic pores, thus lowering the dielectric constant of thecured patternable low-k material. The pore size (diameter) should beless than 10 nm, preferably less than 5 nm, and more preferably lessthan 2 nm.

Illustrative polymers for the patternable low-k material 18 include, butare not limited to, siloxane, silane, carbosilane, oxycarbosilane,silsesquioxanes-type polymers including caged, linear, branched or acombination thereof. In one embodiment, the first patternable material18 comprises a blend of these photo/acid-sensitive polymers. Examples ofpatternable low-k materials useable with the present disclosure aredisclosed in U.S. Pat. Nos. 7,041,748, 7,056,840, and 6,087,064, as wellas U.S. Ser. Nos. 11/750,356, filed May 18, 2007, now U.S. PatentApplication Publication No. 2008/0286467, Ser. No. 12/047,435, filedMar. 13, 2008, and Ser. No. 12/126,287, filed May 23, 2008 all of whichare incorporated herein by reference in their entirety. The dielectricconstant of the patternable low-k material 18 after cure is generally nomore than 4.3. The dielectric constant may be greater than 1 and up to4.3, more preferably from 1 to 3.6, even more preferably from 1 to 3.0,further more preferably from 1 to 2.5, with from 1 to 2.0 being mostpreferred.

The first patternable low-k material 18 is formed from a compositionthat includes at least one of the above mentioned polymers, copolymersor blends, a photoacid generator, a base additive and a solventtypically used in a photoresists. When the first patternable low-kmaterial 18 is a negative-tone patternable low-k material, it may beformed from a composition optionally including an additionalcross-linker. This additional cross-linker can be a small compound (ascompared with a polymer or copolymer) or a polymer, a copolymer, or ablend including at least two of any combination of polymers and/orcopolymers, wherein the polymers include one monomer and the copolymersinclude at least two monomers and wherein the monomers of the polymersand the monomers of the copolymers are selected from a siloxane, silane,carbosilane, oxycarbosilane, silsesquioxane, alkyltrialkoxysilane,tetra-alkoxysilane, unsaturated alkyl substituted silsesquioxane,unsaturated alkyl substituted siloxane, unsaturated alkyl substitutedsilane, an unsaturated alkyl substituted carbosilane, unsaturated alkylsubstituted oxycarbosilane, carbosilane substituted silsesquioxane,carbosilane substituted siloxane, carbosilane substituted silane,carbosilane substituted carbosilane, carbosilane substitutedoxycarbosilane, oxycarbosilane substituted silsesquioxane,oxycarbosilane substituted siloxane, oxycarbosilane substituted silane,oxycarbosilane substituted carbosilane, and oxycarbosilane substitutedoxycarbosilane.

When the first patternable low-k material 18 is a positive-tonepatternable low-k material, it is formed from a composition thatincludes at least one of the above mentioned polymers, copolymers orblends, a photoacid generator a base additive and a solvent typicallyused in a photoresists. The photoacid generators, base additives andsolvents are well known to those skilled in the art and, as such,details regarding those components are not fully provided.

In a preferred embodiment, the first patternable low-k material 18 is achemically amplified positive-tone or negative-tone patternable low-kmaterial that comprises a silsesquioxane polymer or copolymer or a blendof at least two of any combination of polymers and/or copolymers. Thisphoto/acid sensitive silsesquioxane polymer or copolymer may undergo aphoto/acid catalyzed chemical transformation to form circuit patternsafter lithographic patterning. When the first patternable low-k material18 is a chemically amplified positive-tone patternable low-k material,it typically undergoes a de-protection reaction to render the exposedarea soluble in a developer; when the first patternable low-k material18 is a chemically amplified negative-tone patternable low-k material,it typically undergoes a cross-linking reaction (to itself or through anadditional cross-linker) to render it insoluble in a developer in theexposed regions during lithographic processing. Therefore, integratedcircuit patterns can be generated during standard semiconductorlithography process. Furthermore, these integrated circuit patternsmaintain their pattern integrity during the post patterning cure processto convert the patternable low-k material from a resist into a low-kmaterial. Examples of such photo/acid sensitive silsesquioxane polymersor copolymers include poly(methylsilsesquioxane) (PMS),poly(p-hydroxybenzylsilsesquioxane) (PHBS),polyp-hydroxyphenylethylsilsesquioxane) (PHPES),poly(p-hydroxyphenylethylsilsesquioxane-co-p-hydroxy-alpha-methylbenzylsilsesquioxane) (PHPE/HMBS),poly(p-hydroxyphenylethylsilsesquioxane-co-methoxybenzylsilsesquioxane)(PHPE/MBS),poly(p-hydroxyphenylethylsilsesquioxane-co-t-butylsilsesquioxane)(PHPE/BS),poly(p-hydroxyphenylethylsilsesquioxane-co-cyclohexylsilsesquioxane)(PHPE/CHS),poly(p-hydroxyphenylethylsilsesquioxane-co-phenylsilsesquioxane)(PHPE/PS),poly(p-hydroxyphenylethylsilsesquioxane-co-bicycloheptylsilsesquioxane)(PHPE/BHS), polyp-hydroxy-alpha-methylbenzylsilsesquioxane) (PHMBS),polyp-hydroxy-alpha-methylbenzylsilsesquioxane-co-p-hydroxybenzylsilsesquioxane)(PHMB/HBS),poly(p-hydroxy-alpha-methylbenzylsilsesquioxane-co-methoxybenzylsilsesquioxane)(PHMB/MBS),poly(p-hydroxy-alpha-methylbenzylsilsesquioxane-co-t-butylsilsesquioxane)(PHMB/BS),poly(p-hydroxy-alpha-methylbenzylsilsesquioxane-co-cyclohexylsilsesquioxane)(PHMB/CHS),poly(p-hydroxy-alpha-methylbenzylsilsesquioxane-co-phenylsilsesquioxane)(PHMB/PS),poly(p-hydroxy-alpba-methylbenzylsilsesquioxane-co-bicycloheptylsilsesqioxane)(PHMB/BHS),poly(p-hydroxybenzysilsesquioxane-co-p-hydroxyphenylethylsilsesquioane)(PHBI/HPES), andpoly(p-hydroxy-alpha-methylbenzylsilsesquioxane-co-p-alpha-methylbenzylsilsesquioxane)(PHMB/MBS). In one embodiment, the patternable low-k material 18 is acopolymer of at least two monomers selected from an alkyltrialkoxysilaneand/or a tetra-alkoxysilane. Preferred copolymers are derived from atleast two monomers selected from methyltrimethoxysilane,methyltriethoxysilane, ethyltrimethoxysilane, or ethyltriethoxysilane,as the alkyltrialkoxysilane monomer and tetra-methoxysilane ortetra-ethoxysilane, as the tetra-alkoxysilane monomer.

In another embodiment, the first patternable low-k material 18 comprisesa polymer of one monomer or a copolymer of at least two monomersselected from alkyltrialkoxysilane, tetra-alkoxysilane, unsaturatedalkyl (such as vinyl) substituted silsesquioxane, unsaturated alkylsubstituted siloxane, unsaturated alkyl substituted silane, anunsaturated alkyl substituted carbosilane, unsaturated alkyl substitutedoxycarbosilane, carbosilane substituted silsesquioxane, carbosilanesubstituted siloxane, carbosilane substituted silane, carbosilanesubstituted carbosilane, carbosilane substituted oxycarbosilane,oxycarbosilane substituted silsesquioxane, oxycarbosilane substitutedsiloxane, oxycarbosilane substituted silane, oxycarbosilane substitutedcarbosilane, and oxycarbosilane substituted oxycarbosilane.

In one embodiment, the first patternable low-k material 18 comprises asilsesquioxane polymer. It may be linear, branched, caged compound or acombination thereof having the following general structural formula:

where, m and n represent the number of repeating units, R¹ represents agroup which may comprise one or more functional groups which may providepolymer solubility in an aqueous base and provide functional groups forcross-linking, and R² represents a group which may comprise a carbonfunctionality which may control polymer dissolution rate in an aqueousbase and/or an imaging function for positive-tone or negative-tonepatterning. Subscripts m and n may be integers in the range from 0 to50000, such as 1 to 5000 for example. R¹ may not be the same as R².

R¹ is not limited to any specific functional group, and may comprisefunctional groups which are substituted with —OH groups, —C(O)OH groups,—F, or a combination thereof R¹ may comprise linear or branched alkyls,cycloalkyls, aromatics, arenes, or acrylics. For example, R¹ may be:

or the like.

R² is not necessarily limited to any specific functional group, and maycomprise hydrogen, or linear or branched alkyls, cylcoalkyls, aromatics,arenes, acrylates, or a combination thereof. For example R² may be:

or the like.

The R¹ and R² proportions and structures may be selected to provide amaterial suitable for photolithographic patterning processes.

In one embodiment, the first patternable low-k material 18 is anegative-tone patternable low-k dielectric material comprising a blendincluding at least two of any combination of polymers and/or copolymers,wherein the polymers include one monomer and the copolymers include atleast two monomers and wherein the monomers of the polymers and themonomers of the copolymers are selected from a siloxane, silane,carbosilane, oxycarbosilane, silsesquioxane, alkyltrialkoxysilane,tetra-alkoxysilane, unsaturated alkyl substituted silsesquioxane,unsaturated alkyl substituted siloxane, unsaturated alkyl substitutedsilane, an unsaturated alkyl substituted carbosilane, unsaturated alkylsubstituted oxycarbosilane, carbosilane substituted silsesquioxane,carbosilane substituted siloxane, carbosilane substituted silane,carbosilane substituted carbosilane, carbosilane substitutedoxycarbosilane, oxycarbosilane substituted silsesquioxane,oxycarbosilane substituted siloxane, oxycarbosilane substituted silane,oxycarbosilane substituted carbosilane, and oxycarbosilane substitutedoxycarbosilane. The polymers in the blend may be miscible with eachother. The first polymer or copolymer of the polymer blend has beendescribed above.

In some instances, the second polymer of the polymer blend of thisembodiment may comprise a polymer of one monomer or a copolymerincluding at least two monomers and wherein the monomers of the polymersand the monomers of the copolymers are selected from a siloxane, silane,carbosilane, oxycarbosilane, silsesquioxane, alkyltrialkoxysilane,tetra-alkoxysilane, unsaturated alkyl substituted silsesquioxane,unsaturated alkyl substituted siloxane, unsaturated alkyl substitutedsilane, an unsaturated alkyl substituted carbosilane, unsaturated alkylsubstituted oxycarbosilane, carbosilane substituted silsesquioxane,carbosilane substituted siloxane, carbosilane substituted silane,carbosilane substituted carbosilane, carbosilane substitutedoxycarbosilane, oxycarbosilane substituted silsesquioxane,oxycarbosilane substituted siloxane, oxycarbosilane substituted silane,oxycarbosilane substituted carbosilane, and oxycarbosilane substitutedoxycarbosilane. In one embodiment, the second polymer of the polymerblend may comprise a copolymer at least two monomers selected fromsiloxane, silane, silsesquioxane, carbosilane, or oxycarbosilanemoieties. In another embodiment of the present invention, the secondpolymer of the polymer blend may comprise a copolymer of at least twomonomers selected from an alkyltrialkoxysilane and/or atetra-alkoxysilane. The molar ratio of the alkyltrialkoxysilane monomerin the copolymer ranges from 0 to 100%. The weight average molecularweight of the copolymer range from 100-5,000,000 g/mol, preferably500-50,000 g/mol. Preferred second polymers of the polymer blend arecopolymers derived from at least two monomers selected frommethyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, orethyltriethoxysilane, as the alkyltrialkoxysilane monomer andtetra-methoxysilane or tetra-ethoxysilane, as the tetra-alkoxysilanemonomer. In one embodiment, the second polymer of the polymer blend is acopolymer of methylsilsesquioxane and tetra-alkoxysilane.

In another embodiment, the second polymer of the polymer blend is asilsesquioxane polymer comprising a polymer having the structuralformula:

wherein R³ may be a functional group comprising alkyls, cycloalkyls,aryl, or a combination thereof, and wherein x represents the number ofrepeating units and may be an integer in a range from 4 to 50000. Forexample, R³ may be:

or the like.

In one embodiment, the polysilsesquioxane may bepoly(methylsilsesquioxane), where R³ is a methyl group, and x is aninteger from 10 to 1,000. In other embodiments, x may be greater than1,000. The polysilsesquioxane may also comprise a copolymer withsiloxane, silane, carbosilane, oxycarbosilane, alkyltrialkoxysilane, ortetra-alkoxysilane. The polysilsesquioxane structure may be caged,linear, branched, or a combination thereof. The silsesquioxane polymersdescribed herein may comprise end groups comprising silanols,halosilanes, acetoxysilanes, silylamines, alkoxysilanes, or acombination thereof, which may undergo condensation reactions in thepresence of an acid (such as an acid generated by a photoacid generatorunder exposure to radiation), followed by thermal baking. Polymermolecules of the polysilsesquioxane may undergo chemical crosslinkingwith the first polymer or copolymer of the polymer blend, the secondpolysilsesquioxane polymer or copolymer in the polymer blend itself, ora combination of these.

In one embodiment, the polysilsesquioxane may be the silsesquioxanecopolymer LKD-2056 or LKD2064 (products of JSR Corporation) whichcontains silanol end groups. Such crosslinking may be not limited tosilanols, but may also include halosilanes, acetoxysilanes, silylamines,and alkoxysilanes. The silsesquioxane polymers described herein mayundergo chemical crosslinking, including photoacid-catalyzedcrosslinking, thermally induced crosslinking, or a combination of these,such as condensation reactions of silanol end groups, for example.

The second silsesquioxane polymers or copolymers in the polymer blendmay have a weight averaged molecular weight in the range from 200 to5,000,000 g/mol, such as from 1500 to 10,000 g/mol, for example.

In another embodiment, the first patternable low-k material 18 is anegative-tone patternable low-k material comprising acarbosilane-substituted silsesquioxane polymer that may be a linear,branched, caged compound or a combination thereof, having the followinggeneral structural formula:

where, a, b, and c represent the number of each of the repeating units,R⁴, R⁵, R⁶, R⁷, and R⁸ are carbon-containing groups, and R⁹ is an alkoxygroup. R⁶, R⁷ and R⁸ may each independently represent a hydrocarbongroup comprising 1 to 6 carbon atoms.

R⁴, R⁵, R⁶, R⁷, R⁸, R⁹ may be non-identical groups. Subscripts a, b, andc represent the number of repeating units in the polymer chain.Subscripts q and r may be integers in a range from 0 to 3. Subscript smay be an integer in a range from 1 to 3. Subscripts a and c may beintegers greater than zero. For example a and c may each independentlybe in a range from 1 to 5,000. Subscript b may be an integer greaterthan or equal to zero. For example, b may be an integer in a range from0 to 5,000.

R⁴ may represent a group which comprises one or more functional groupswhich provide polymer solubility in an aqueous base and functionalgroups for a cross-linking reaction. Each instance of R⁴ is not limitedto any specific functional group, and may comprise a functional groupwhich is substituted with one or more —OH groups, —C(O)OH groups, —F, ora combination thereof R⁴ may comprise linear or branched alkyls,cycloalkyls, aromatics, arenes, or acrylics. Examples of R⁴ include:

or the like.

R⁵ may represent a group which comprises a carbon functionalitycomprising at least one carbon atom, where the carbon functionalitycontrols polymer dissolution of the polymer into an aqueous base. Thestructure (e.g., size, chain length, etc.) of R⁵ may affect thedissolution rate of the polymer into an aqueous base. Balancing of thedissolution-controlling group, R⁵, with the solubility and cross-linkingcontrolling group, R⁴, allows properties such as dissolution rate andaqueous base solubility to be appropriately adjusted. R⁵ is notnecessarily limited to any specific functional group, and may compriselinear or branched alkyls, cylcoalkyls, aromatics, arenes, acrylates, ora combination thereof: Examples of R⁵ include:

or the like.

R⁶ is not limited to any specific alkoxy group. Examples of R⁶ includelinear or branched alkoxys, cycloalkoxy, and acetoxy groups.

The specific proportions and structures of R⁴, R⁵, and R⁶ may beselected to provide a material suitable for photolithographic patterningprocesses.

In another embodiment, the first patternable low-k material 18 is anegative-tone patternable low-k material comprising a polymer blend of afirst polymer or copolymer and a second polymer or copolymer wherein thefirst polymer is the carbosilane-substituted silsesquioxane polymerdescribed above and the second polymer is polymer of one monomer or acopolymer of at least two monomers selected from siloxane, silane,silsesquioxane, carbosilane, or oxycarbosilane moieties. In oneembodiment of the present invention, the second polymer of the polymerblend may comprise a copolymer of at least two monomers selected from analkyltralkoxysilane and/or a tetra-alkoxysilane. The molar ratio of thealkyltrialkoxysilane monomer in the copolymer ranges from 0 to 100%. Theweight average molecular weight of the copolymer range from100-5,000,000 g/mol, preferably 500-50,000 g/mol. Preferred secondpolymers of the polymer blend are copolymers derived from at least twomonomers selected from methyltrimethoxysilane, methyltriethoxysilane,ethyltrimethoxysilane, or ethyltriethoxysilane, as thealkyltrialkoxysilane monomer and tetramethoxysilane ortetra-ethoxysilane, as the tetra-alkoxysilane monomer. In oneembodiment, the second polymer of the polymer blend is a copolymer ofmethylsilsesquioxane and tetraalkoxysilane.

In another embodiment, the negative-tone carbosilane-substitutedsilsesquioxane patternable low-k composition may be a polymer blend of afirst polymer and a second polymer wherein the first polymer is thecarbosilane-substituted silsesquioxane polymer described above and thesecond polymer of the polymer blend is a silsesquioxane polymercomprising a polymer having the structural formula:

wherein R³ may be a functional group comprising alkyls, cycloalkyls,aryl, or a combination thereof, and wherein x represents the number ofrepeating units and may be an integer in a range from 4 to 50000. Forexample, R³ may be:

or the like.

In one embodiment, the polysilsesquioxane may bepoly(methylsilsesquioxane), where R³ is a methyl group, and x is aninteger from 10 to 1,000. In other embodiments, x may be greater than1,000. The polysilsesquioxane may also comprise a copolymer withsiloxane, silane, carbosilane, oxycarbosilane, alkyltrialkoxysilane, ortetra-alkoxysilane. The polysilsesquioxane structure may be caged,linear, branched, or a combination thereof. The silsesquioxane polymersor copolymers described herein may comprise end groups comprisingsilanols, halosilanes, acetoxysilanes, silylamines, alkoxysilanes, or acombination thereof, which may undergo condensation reactions in thepresence of an acid (such as an acid generated by a photoacid generatorunder exposure to radiation), followed by thermal baking. Polymermolecules of the polysilsesquioxane may undergo chemical crosslinkingwith the first polymer or copolymer of the polymer blend, the secondpolysilsesquioxane polymer or copolymer in the polymer blend itself, ora combination of these. In one embodiment, the polysilsesquioxane may bethe silsesquioxane copolymer LKD-2056 or LKD2064 (products of JSRCorporation) which contains silanol end groups. Such crosslinking may benot limited to silanols, but may also include halosilanes,acetoxysilanes, silylamines, and alkoxysilanes. The silsesquioxanepolymers described herein may undergo chemical crosslinking, includingphotoacid-catalyzed crosslinking, thermally induced crosslinking, or acombination of these, such as condensation reactions of silanol endgroups, for example.

The silsesquioxane polymers representing the second polymer of thepolymer blend described for this embodiment may have a weight averagedmolecular weight in the range from 200 g/mol to 500,000 g/mol, such asfrom 1500 g/mol to 10,000 g/mol, for example.

In another embodiment, compositions containing a blend of at least twoof any combination of a silsesquioxane polymer and/or a silsesquioxanecopolymer are employed. The silsesquioxane polymer or copolymer in theblend may be selected from the silsesquioxane polymers or copolymersdescribed above or may be selected from other silsesquioxane polymers orcopolymers such as, for example, poly(methyl-silsesquioxane) (PMS),poly(p-hydroxybenzylsilsesquioxane) (PHBS),poly(p-hydroxybenzylsilsesquioxane-co-methoxybenzylsilsesquioxane)(PHB/MBS),polyp-hydroxy-alpha-methylbenzylsilsesquioxane-co-p-alpha-methylbenzylsilsesquioxane)(PHMB/MBS), poly(p-hydroxybenzylsilsesquioxane-co-t-butylsilsesquioxane)(PHB/BS),poly(p-hydroxybenzylsilsesquioxane-co-cyclohexylsilsesquioxane)(PHB/CHS), poly(p-hydrooxybenzylsilsesquioxane-co-phenylsilsesquioxane)(PHB/PS),poly(p-hydroxybenzylsilsesquioxane-co-bicycloheptylsilsesquioxane)(PHB/BHS), and caged silsesquioxanes such asoctakis(glycidyloxypropyl)dimethylsilyloxy)silsesquioxane,octakis[cyclohexenyl epoxide) dimethylsilyloxy]silsesquioxane,octakis[4-(hydroxyphenylethyl)dimethylsilyloxy]silsesquioxane, andoctakis[{2-(1′,1′-bis(trifluoromethyl)-1′-hydroxyethyl)norbornyl}dimethylsilyloxy]silsesquioxane.If desired, a combination of different Si-containing polymers may beused in the blend with the non-Si-containing polymers, such as a poregenerator.

In yet another embodiment, the first patternable low-k material 18comprises a copolymer of at least two monomers selected from analkyltrialkoxysilane and/or a tetra-alkoxysilane. Preferred copolymersare derived from at least two monomers selected frommethyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, orethyltriethoxysilane, as the alkyltrialkoxysilane monomer andtetra-methoxysilane or tetra-ethoxysilane, as the tetra-alkoxysilanemonomer.

In a preferred embodiment for negative-tone patternable low-k materialstwo miscible, or compatible, silsesquioxanes are employed. The firstsilsesquioxane polymer or copolymer is a linear, branched, cagedcompound or combination thereof having the following structural formula:

wherein each occurrence of R¹⁰ is one or more acidic functional groupsfor base solubility and provides functional groups for cross-linking;each occurrence of R¹¹ is a carbon functionality for controlling polymerdissolution rate in an aqueous base; R¹⁰ is not equal to R¹¹; j and krepresent the number of repeating units; j is an integer; and k is zeroor an integer greater than zero.

In the present invention, R¹⁰ is not limited to any specific functionalgroup, and is preferably selected from among linear or branched alkylswhich are substituted with OH, C(O)OH, and/or F; cycloalkyls which aresubstituted with OH, C(O)OH, and/or F; aromatics which are substitutedwith OH, C(O)OH, and/or F; arenes that are substituted with OH, C(O)OH,and/or F; and acrylics which are substituted with OH, C(O)OH, and/or F.Examples of preferred R¹⁰ include:

In the present invention, R¹¹ is not limited to any specific carbonfunctional group, and is preferably selected from among linear orbranched alkyls, cylcoalkyls, aromatics, arenes, and acrylates.

The silsesquioxane polymers or copolymers of this embodiment have aweight averaged molecular weight of 400 to 500,000, and more preferablefrom 1500 to 10,000. The R¹⁰ and R¹¹ proportions and structures areselected to provide a material suitable for photolithographic processes.

A second polymer component of the blend material includes but is notlimited to a family of organosilicates known as silsesquioxanes havingthe structural formula:

wherein R³ may be a functional group comprising alkyls, cycloalkyls,aryl, or a combination thereof, and wherein x represents the number ofrepeating units and may be an integer in a range from 4 to 50000. Forexample, R³ may be:

or the like.

In one embodiment, the polysilsesquioxane may bepoly(methylsilsesquioxane), where R³ is a methyl group, and x is aninteger from 10 to 1,000. In other embodiments, x may be greater than1,000. The polysilsesquioxane may also comprise a copolymer withsiloxane, silane, carbosilane, oxycarbosilane, alkyltrialkoxysilane, ortetra-alkoxysilane. The polysilsesquioxane structure may be caged,linear, branched, or a combination thereof. The silsesquioxane polymersor copolymers described herein may comprise end groups comprisingsilanols, halosilanes, acetoxysilanes, silylamines, alkoxysilanes, or acombination thereof, which may undergo condensation reactions in thepresence of an acid (such as an acid generated by a photoacid generatorunder exposure to radiation), followed by thermal baking. Polymermolecules of the polysilsesquioxane may undergo chemical crosslinkingwith the first polymer or copolymer of the polymer blend, the secondpolysilsesquioxane polymer or copolymer in the polymer blend itself, ora combination of these. In one embodiment, the polysilsesquioxane may bethe silsesquioxane copolymer LKD-2056 or LKD2064 (products of JSRCorporation) which contains silanol end groups. Such crosslinking may benot limited to silanols, but may also include halosilanes,acetoxysilanes, silylamines, and alkoxysilanes. The silsesquioxanepolymers described herein may undergo chemical crosslinking, includingphotoacid-catalyzed crosslinking, thermally induced crosslinking, or acombination of these, such as condensation reactions of silanol endgroups, for example.

A third component of a negative-tone patternable low-k composition is aphotosensitive acid generator (PAG). Examples of preferred PAGs include:-(trifluoro-methylsulfonyloxy)-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide(MDT), onium salts, aromatic diazonium salts, sulfonium salts,diaryliodonium salts, and sulfonic acid esters of N-hydroxyamides or-imides, as disclosed in U.S. Pat. No. 4,371,605. The content of the'605 patent is incorporated herein by reference. A weaker acid generatedfrom a PAG such as N-hydroxy-naphthalimide (DDSN) may be used.Combinations of PAGs may be used.

The composition of the silsesquioxane polymers or copolymers in theblend formulation is 1% to 99% of the total polymer composition. In apreferred embodiment, the composition of the acid sensitive polymer is20% to 80% of the total polymer composition, and even more preferred,30% to 60%.

Condensation in the presence of an acid generated by a photoacidgenerator under exposure to radiation is not limited to silanols, butmay also include halosilanes, acetoxysilanes, silylamines, andalkoxysilanes. Organic crosslinking agents, such asmethylphenyltetramethoxymethyl glycouril (methylphenyl powderlink), mayalso be included in the formulation. Although photoacid generators arepreferred for crosslinking, photobase generators can also be used forcrosslinking silanol polymers or copolymers.

The first patternable low-k material 18 also typically includes acasting solvent to dissolve the other components. Examples of suitablecasting solvent include but are not limited to ethoxyethylpropionate(EEP), a combination of EEP and γ-butyrolactone, propylene-glycolmonomethylether alcohol and acetate, propyleneglycol monopropyl alcoholand acetate, and ethyl lactate. Combinations of these solvents may alsobe used.

In optimizing the photolithography process, an organic base may be addedto the formulation. The base employed in the present invention may beany suitable base known in the resist art. Examples of bases includetetraalkylammonium hydroxides, cetyltrimethylammonium hydroxide, and1,8-diaminonaphthalene. The compositions are not limited to any specificselection of base.

In yet another embodiment, the first patternable low-k material 18 is achemically amplified positive-tone patternable low-k material comprisinga silicon-containing polymer. The silicon-containing polymer employedmay be a homopolymer or a copolymer. Suitable types of suchsilicon-containing polymers include a polymer, a copolymer, a blendincluding at least two of any combination of polymers and/or copolymers,wherein said polymers include one monomer and said copolymers include atleast two monomers and wherein said monomers of said polymers and saidmonomers of said copolymers are selected from a siloxane, silane,carbosilane, oxycarbosilane, silsesquioxane, alkyltrialkoxysilane,tetra-alkoxysilane, unsaturated alkyl substituted silsesquioxane,unsaturated alkyl substituted siloxane, unsaturated alkyl substitutedsilane, an unsaturated alkyl substituted carbosilane, unsaturated alkylsubstituted oxycarbosilane, carbosilane substituted silsesquioxane,carbosilane substituted siloxane, carbosilane substituted silane,carbosilane substituted carbosilane, carbosilane substitutedoxycarbosilane, oxycarbosilane substituted silsesquioxane,oxycarbosilane substituted siloxane, oxycarbosilane substituted silane,oxycarbosilane substituted carbosilane, and oxycarbosilane substitutedoxycarbosilane. Highly preferred silicon-backbone polymers are selectedfrom the group consisting of poly(hydroxyphenyl alkyl)silsesquioxanesand poly(hydroxyphenyl alkyl) siloxanes, wherein the alkyl is a C₁₋₃₀moiety. These preferred silicon-containing polymers are preferably fullyor partially protected with acid-sensitive protecting groups.

In one embodiment, the first patternable low-k material 18 is achemically amplified positive-tone patternable low-k material comprisinga polymer of one monomer or a copolymer of at least two monomers whereina silicon-containing substituent is chemically bonded to the monomer ofthe polymers or copolymers. The silicon-containing substituent may ormay not be acid sensitive. Typically, however the substituent is acidsensitive when containing a C₂ alkyl moiety. Preferably, thesilicon-containing substituent is attached to a monomer selected fromthe group consisting of hydroxystyrene, an acrylate, a methacrylate, anacrylamide, a methacrylamide, itaconate, an itaconic half ester or acycloolefin. Preferred silicon-containing substituents include:siloxane, silane and cubic silsesquioxanes. The silicon-containingpolymer may further include silicon-free monomers such as those selectedfrom the group consisting of styrene, hydroxystyrene, acrylic acid,methacrylic acid, itaconic acid and an anhydride such as maleicanhydride and itaconic anhydride.

Preferred monomers containing silicon-containing substituents aretrimethylsilyl alkyl acrylate, trimethylsilyl alkyl methacrylate,trimethylsilyl alkyl itaconate, tris(trimethylsilyl)silyl alkyl acrylatetris(trimethylsilyl)silyl alkyl methacrylate, tris(trimethylsilyl)silylalkyl itaconate, tris(trimethylsilyloxy)silyl alkyl acrylate,tris(trimethylsilyloxy)silyl alkyl methacrylate,tris(trimethylsilyloxy)silyl alkyl itaconate, alkylsilyl styrene,trimethylsilylmethyl(dimethoxy)silyloxy alkyl acrylate,trimethylsilylmethyl(dimethoxy)silyloxy alkyl methacrylate,trimethylsilylmethyl(dimethoxy)silyloxy alkyl itaconate, trimethylsilylalkyl norbornene-5-carboxylate alkyl, tris(trimethylsilyl)silyl alkylnorbornene-5-carboxylate and tris(trimethylsilyloxy)silyl alkylnorbornene-5-carboxylate, wherein alkyl is a C₁₋₅ moiety.

Highly preferred species of these monomers are3-(3,5,7,9,11,13,15-heptacyclopentylpentacyclo[9.5.1.13,9.15,15.17,13]-octasiloxan-1-yl)propylmethacrylate,1,3,5,7,9,1,13-heptacyclopentyl-15-vinylpentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane,methacrylamidotrimethylsilane,O-(methacryloxyethyl)-N-(triethoxysilylpropyl)urethane,methacryloxyethoxytrimethylsilane,N-(3-methacryloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane,(methacryloxymethyl)bis(trimethylsiloxy)methylsilane,(m,p-vinylbenzyloxy)trimethylsilane,methacryloxypropyltris(trimethylsiloxy)silane,methacryloxytrimethylsilane,3-methacryloxypropylbis(trimethylsiloxy)methylsilane,3-methacryloxypropyldimethychlorosilane,methacryloxypropyldimethylethoxysilane,methacryloxypropyldimethylmethoxysilane,methacryloxypropylheptacyclopentyl-T8-silsesquioxane,methacryloxypropylmethyldichlorosilane,methacryloxypropylmethyldiethoxysilane,methacryloxypropylmethyldimethoxysilane,(methacryloxymethyl)dimethylethoxysilane,(methacryloxymethylphenyldimethylsilanephenyldimethylsilyl)methymethacrylate,methacryloxymethyltriethoxysilane, methacryloxymethyltrimethoxysilane,methacryloxymethyltris(trimethylsiloxy)silane,O-methacryloxy(polyethyleneoxy)trimethylsilane,methacryloxypropylpentamethyldisiloxane, methacryloxypropylsilatrane,methacryloxypropylsiloxane macromer, methacryloxypropyl terminatedpolydimethylsiloxane, methacryloxypropyltrichlorosilane,methacryloxypropyltriethoxysilane, methacryloxypropyltrimethoxysilane,methacryloxypropyltris(methoxyethoxy)silane,p-(t-butyldimethylsiloxy)styrene, butenyltriethoxysilane,3-butenyltrimethylsilane, (3-acryloxypropyl)trimethoxysilane,(3-acryloxypropyl)tris(trimethylsiloxy)silane,O-(trimethylsilyl)acrylate, 2-trimethylsiloxyethlacrylate,N-(3-acryloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane,(3-acryloxypropyl)dimethylmethoxysilane,(3-acryloxypropyl)methylbis(trimethylsiloxy)silane,(3-acryloxypropyl)methyldichlorosilane, and(3-acryloxypropyl)methyldimethoxysilane,(3-acryloxypropyl)trichlorosilane.

When the first patternable low-k dielectric material 18 is apositive-tone patternable low-k dielectric material comprisingcopolymers, the extent of protection and the amount of co-monomerpresent are such that the patternable low-k material resist compositionwill provide good lithography performance, i.e., high resolution andgood process window. It should also maintain pattern integrity afterpost cure processing patterning. Examples of protecting groups which canbe employed are cyclic and branched (secondary and tertiary) aliphaticcarbonyls, esters or ethers containing from 3 to 30 carbon atoms,acetals, ketals and aliphatic silylethers.

Examples of cyclic or branched aliphatic carbonyls that may be employedin the present invention include, but are not limited to: phenoliccarbonates; t-alkoxycarbonyloxys such as t-butoxylcarbonyloxy andisopropyloxycarbonyloxy. A highly preferred carbonate ist-butoxylcarbonyloxy.

Some examples of cyclic and branched ethers that may be employed in thepresent invention include, but are not limited to benzyl ether andt-alkyl ethers such t-butyl ether. Of the aforesaid ethers, it is highlypreferred to use t-butyl ether.

Examples of cyclic and branched esters that can be employed arecarboxylic esters having a cyclic or branched aliphatic substituent suchas t-butyl ester, isobornyl ester, 2-methyl-2-admantyl ester, benzylester, 3-oxocyclohexanyl ester, dimethylpropylmethyl ester, mevaloniclactonyl ester, 3-hydroxy-g-butyrolactonyl ester,3-methyl-g-butylrolactonyl ester, bis(trimethylsilyl)isopropyl ester,trimethylsilylethyl ester, tris(trimethylsilyl)silylethyl ester andcumyl ester.

Some examples of acetals and ketals that can be employed include, butare not limited to phenolic acetals and ketals as well astetrahydrofuranyl, tetrahydropyranyl, 2-ethoxyethyl,methoxycyclohexanyl, methoxycyclopentanyl, cyclohexanyloxyethyl,ethoxycyclopentanyl, ethoxycyclohexanyl, methoxycycloheptanyl andethoxycycloheptanyl. Of these, it is preferred that amethoxycyclohexanyl ketal be employed.

Illustrative examples of silylethers that can be employed include, butare not limited to: trimethylsilylether, dimethylethylsilylether anddimethylpropylsilylether. Of these silylethers, it is preferred thattrimethylsilylether be employed.

In one embodiment, the first patternable low-k material 18 is apositive-tone patternable low-k dielectric material comprising a blendincluding at least two of any combination of polymers and/or copolymers,wherein the polymers include one monomer and the copolymers include atleast two monomers and wherein the monomers of the polymers and themonomers of the copolymers are selected from a siloxane, silane,carbosilane, oxycarbosilane, silsesquioxane, alkyltrialkoxysilane,tetra-alkoxysilane, unsaturated alkyl substituted silsesquioxane,unsaturated alkyl substituted siloxane, unsaturated alkyl substitutedsilane, an unsaturated alkyl substituted carbosilane, unsaturated alkylsubstituted oxycarbosilane, carbosilane substituted silsesquioxane,carbosilane substituted siloxane, carbosilane substituted silane,carbosilane substituted carbosilane, carbosilane substitutedoxycarbosilane, oxycarbosilane substituted silsesquioxane,oxycarbosilane substituted siloxane, oxycarbosilane substituted silane,oxycarbosilane substituted carbosilane, and oxycarbosilane substitutedoxycarbosilane. The polymers in the blend may be miscible with eachother. The first polymer or copolymer of the polymer blend has beendescribed above.

In one embodiment, the first patternable low-k material 18 is apositive-tone patternable low-k material comprising a polymer blend ofat least two silsesquioxane polymers or copolymers. The polymers orcopolymers in the blend may be miscible with each other. The firstsilsesquioxane polymer or copolymer may be linear, branched, cagedcompound or a combination thereof having the following generalstructural formula:

where, d, e and f represent the number of each of the repeating units,R¹² represents a carbon functionality (the carbon functionalitycomprising at least one carbon atom) having an acid-labile protectinggroup, R¹³ represents a group which may comprise one or more functionalgroups which provide polymer solubility in aqueous base, and R¹⁴represents a group which may comprise a carbon functionality comprisingat least one carbon atom, where the carbon functionality controlspolymer dissolution rate of the polymer blend into aqueous base. R¹²,R¹³, and R¹⁴ may be non-identical groups. Subscripts d, e, and frepresent the number of repeating units. Subscripts d and f may beintegers greater than zero. For example d and f may each independentlybe in a range from 1 to 5,000. Subscript e may be an integer greaterthan or equal to zero. For example, e may be an integer in a range from0 to 5,000.

R¹² is not limited to any specific carbon functional group, and may beselected from among conventional acid sensitive protecting groups, suchas carbonates, tertiary esters, acetals, ketals, the like, and acombination thereof. For example, the acid sensitive protecting groupmay comprise a tert-butylacetate group, where R¹² may be:

R¹³ is not limited to any specific functional group, and may comprisefunctional groups which are substituted with —OH groups, —C(O)OH groups,—F, or a combination thereof R¹³ may comprise linear or branched alkyls,cycloalkyls, aromatics, arenes, or acrylics. For example, R¹³ may be

or the like.

R¹⁴ is not necessarily limited to any specific functional group, and maycomprise linear or branched alkyls, cylcoalkyls, aromatics, arenes,acrylates, or a combination thereof. For example R¹⁴ may be:

or the like.

The specific proportions and structures of R¹², R¹³, and R¹⁴ may beselected to provide a material suitable for photolithographic patterningprocesses.

In one embodiment, the second polymer of the polymer blend of thisembodiment of positive-tone patternable low-k material may comprise apolymer of one monomer or a copolymer including at least two monomersand wherein the monomers of the copolymers are selected from a siloxane,silane, carbosilane, oxycarbosilane, silsesquioxane,alkyltrialkoxysilane, tetra-alkoxysilane, unsaturated alkyl substitutedsilsesquioxane, unsaturated alkyl substituted siloxane, unsaturatedalkyl substituted silane, an unsaturated alkyl substituted carbosilane,unsaturated alkyl substituted oxycarbosilane, carbosilane substitutedsilsesquioxane, carbosilane substituted siloxane, carbosilanesubstituted silane, carbosilane substituted carbosilane, carbosilanesubstituted oxycarbosilane, oxycarbosilane substituted silsesquioxane,oxycarbosilane substituted siloxane, oxycarbosilane substituted silane,oxycarbosilane substituted carbosilane, and oxycarbosilane substitutedoxycarbosilane. In one embodiment, the second polymer of the polymerblend may comprise a copolymer of at least two monomers selected fromsiloxane, silane, silsesquioxane, carbosilane, or oxycarbosilanemoieties. In one embodiment of the present invention, the second polymerof the polymer blend may comprise a copolymer of at least two monomersselected from an alkyltrialkoxysilane and/or a tetra-alkoxysilane. Themolar ratio of the alkyltrialkoxysilane monomer in the copolymer rangesfrom 0 to 100%. The weight average molecular weight of the copolymerrange from 100-5,000,000 g/mol, preferably 500-50,000 g/mol. Preferredcopolymers are derived from at least two monomers selected frommethyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, orethyltriethoxysilane, as the alkyltrialkoxysilane monomer andtetra-methoxysilane or tetra-ethoxysilane, as the tetra-alkoxysilanemonomer.

In another embodiment, the second polymer in the polymer blend for thepositive-tone patternable low-k material is a polymer having thestructural formula:

where R³ may be a carbon functional group having at least one carbonatom and wherein the subscript x represents the number of repeatingunits and may be an integer greater than zero. The subscript q may be ina range from 4 to 50,000, such as from 10 to 1,000 for example. R³ maycomprise, for example, alkyls, cycloalkyls, aryl, or a combinationthereof. Examples of R³ include:

or the like.

In one embodiment, the second silsesquioxane polymer may bepoly(methylsilsesquioxane) or copolymer, where R³ is a methyl group, andx is an integer from 4 to 1,000. In another embodiment, x may be greaterthan 1,000. The second silsesquioxane polymer may also comprise acopolymer with siloxane, silane, carbosilane, oxycarbosilane,alkyltrialkoxysilane, or tetra-alkoxysilane. The second silsesquioxanepolymer or copolymer structure may be caged, linear, branched, or acombination thereof. The silsesquioxane polymers of the presentinvention may comprise end groups comprising silanols, halosilanes,acetoxysilanes, silylamines, alkoxysilanes, and a combination thereof,which may undergo condensation reactions in the presence of an acidgenerated by a photoacid generator under exposure to radiation, followedby thermal baking. Polymer molecules of the second polymer may undergochemical crosslinking with molecules of the first polymer or copolymer,the second polymer or copolymer, or a combination of these. In oneembodiment of the present invention, the second silsesquioxane may bethe silsesquioxane polymer or copolymer LKD 2021, LKD-2056 or LKD 2064(products of JSR Corporation) which contain silanol end groups.

The silsesquioxane polymers or copolymers in the polymer blend may havea weight averaged molecular weight in the range from 400 to 500,000g/mol, such as from 1500 to 10,000 g/mol, for example.

Other components of a positive-tone patternable low-k material include aphoto acid generator, a casting solvent and a base additive. Thesecomponents and their compositions are well known to those skilled in theart and are similar to those in the negative-tone patternable low-kmaterials discussed previously.

The term “photo/acid-sensitive” is used throughout the application todenote imageable functional groups which undergo a chemical reaction inthe presence of an acid generated by a photoacid generator underexposure to radiation. The acid-sensitive imageable functional groupsemployed may include acid-sensitive positive-tone functional groups oracid-sensitive negative-tone functional groups. The negative-toneacid-sensitive functional groups are functional groups for effecting acrosslinking reaction which causes the exposed areas to be insoluble ina developer to form a negative-tone relief image after development. Thepositive-tone acid-sensitive functional groups are acid-sensitiveprotecting groups which cause the exposed region to be soluble in adeveloper to form positive-tone relief images after development.

In one preferred embodiment, a positive-tone patternable low-k material18 is used for via patterning. Either a positive-tone or a negative-tonepatternable low-k material 18 is used for line patterning.

The aforementioned patternable low-k materials act as a photoresist inthe present invention during patterning; they can be positive-tone ornegative-tone, and sensitive to G-line, I-line, DUV (248 nm, 193 nm, 157nm, 126 nm, and EUV (13.4 μm), an electron beam, or an ion beam.

Referring to FIG. 1C, the first patternable low-k material 18 ispattern-wise exposed to form latent images of a desired circuitry. Anoptional post-exposure baking may be required to effect thephotochemical reactions. When performed, the baking step is conducted ata temperature from 60° C. to 200° C., with a baking temperature from 80°C. to 140° C. being even more preferred. The duration of the baking stepvaries from 10 seconds to 600 seconds and is not critical to thepractice of the present invention. After exposure and post-exposurebaking, the latent images are developed into the low-k material with adeveloper, usually 0.263N tetra-methyl-ammonium hydroxide.

The pattern-wise exposing process can be accomplished in a variety ofways, including, for example, through a mask with a lithography stepperor a scanner with an exposure light source of G-line, I-line (365 nm),DUV (248 nm, 193 nm, 157 nm, 126 nm), Extreme UV (13.4 nm), an electronbeam, or an ion beam. The pattern-wise exposing process also includesdirect writing without the use of a mask with, for example, light,electron beam, ion beam, and scanning probe lithography. In oneembodiment, the pattern-wise exposure is accomplished with an exposurelight source of 193 nm wavelength and extreme UV (13.4 nm wavelength).

In another embodiment, the pattern-wise exposure is accomplished withimmersion lithography with an exposure light source of 193 nm wavelengthwherein in a liquid having a refractive index greater than air (1),e.g., water, is placed to fill a space between the final optical elementof a lithography projection system and the patternable low-k material18. When the pattern-wise exposure is accomplished with immersionlithography, the patternable low-k material 18 must be compatible withthe liquid placed between the final optical element of a lithographyprojection system and the patternable low-k material 18. By compatible,it mainly means low leaching of components from the patternable low-kmaterial 18 into the liquid (generally <1.5×10⁻¹¹ mol/Cm²) to avoidcontamination and damage of the final optical element of the lithographyproject system. This compatibility can be achieved by a method selectedfrom adding a separate top coating to the patternable low-k material 18,and adding an appropriate additive to the patternable low-k compositionsuch that it segregates to the top of the patternable low-k film afterprocessing to prevent leaching. This top coating can also acts as a topanti-reflective coating for the patternable low-k material 18. It isconceivable to that use other liquids with higher refractive index thanwater. Examples of these high-index liquids include cyclic hydrocarbon,and high-index nano-particles suspended in an appropriate liquid.

Specifically, FIG. 1C illustrates the structure that is formed afterforming a first pattern within the first patternable low-k material 18.Reference numeral 20 denotes the remaining first patternable low-kmaterial which is not removed during the patterning process. As shownthe remaining first patternable low-k material (or patterned first low-kmaterial) 20 protects portions of the ARC 16, while other portions ofthe ARC 16 are left exposed.

After forming the patterned first low-k dielectric material 20, thelow-k material is typically, but not necessarily always, cured to form acured patterned first low-k material 20′ (See, FIG. 11D) in which thecured low-k material is formed. The curing is optional when the firstpatternable low-k material 18 is negative-tone, but it is generallyrequired when the first patternable low-k material 18 is a positive-tonematerial. This post patterning cure is not required if the patternedfirst patternable low-k material is compatible with the deposition ofthe second patternable low-k material thereon. By compatible herein, itmeans that the deposition of the second patternable low-k material doesnot dissolve or degrade the pattern and the quality of the patternedfirst patternable low-k material.

Curing is performed by a thermal cure, an electron beam cure, anultra-violet (UV) cure, an ion beam cure, a plasma cure, a microwavecure or a combination thereof. The conditions for each of the curingprocess are well known to those skilled in the art and any condition canbe chosen as long as it coverts the patternable low-k material 18 into alow-k film and maintains pattern fidelity.

In another embodiment, an irradiation cure step is performed by acombination of a thermal cure and an ultra-violet (UV) cure wherein thewavelength of the ultra-violet (UV) light is from 50 nm to 300 nm andthe light source for the ultra-violet (UV) cure is a UV lamp, an excimer(exciplex) laser or a combination thereof. The excimer laser may begenerated from at least one of the excimers selected from the groupconsisting of Ar₂*, Kr₂*, F₂, Xe₂*, ArF, KrF, XeBr, XeCl, XeCl, XeF,CaF₂, KrCl, and Cl₂ wherein the wavelength of the excimer laser is inthe range from 50 to 300 nm. Additionally, the light of the ultra-violet(UV) cure may be enhanced and/or diffused with a lens or other opticaldiffusing device known to those skilled in the art.

In one embodiment, this post patterning cure is a combined UV/thermalcure. This combined UV/thermal cure is carried on a UV/thermal curemodule under vacuum or inert atmosphere, such as N₂, He, Ar. Typically,the UV/thermal cure temperature is from 100° C. to 500° C., with a curetemperature from 300° C. to 450° C. being more typical. The duration ofthe UV/thermal cure is from 0.5 min to 30 min with a duration from 1 minto 10 min being more typical. The UV cure module is designed to have avery low oxygen content to avoid degradation of the resultant dielectricmaterials.

After patterning and optionally curing the first patternable low-kmaterial 18, a second patternable low-k material 22 is formed providingthe structure shown in FIG. 1E. The second patternable low-k material 22may comprise the same or different photo-patternable dielectric materialas the first patternable low-k material 18. The deposition processes andthickness mentioned above for the first patternable low-k material 18are each applicable here for the second patternable low-k material 22.Typically, and in the embodiment illustrated, the first patternablelow-k material 18 or the second patternable low-k material 22 is eithera negative-tone or a positive-tone material.

Referring to FIG. 1F, the second patternable low-k material 22 issubjected to an exposure step in which the exposure of the secondpatternable low-k material 22 occurs in an area different from the firstpatterned low-k material 20 (or 20′, if 20 is cured) that remains on thesurface of ARC 16. Typically, this exposure occurs at a half pitchdistance from the edge of the patterned first low-k dielectric material.In FIG. 1F, the area within the second patternable low-k material 22which is denoted by reference numeral 24 denotes the exposed area.

FIG. 1G illustrates the structure of FIG. 1F after further patterning(i.e., development) and curing. The further patterning forms a patternedsecond low-k material on a previous surface on the ARC 16 which does notinclude the patterned first low-k material 20 (or 20′ if 20 is cured).In FIG. 1G, reference numeral 26 denotes the patterned and cured secondlow-k material. The further patterning of the second patternable low-kmaterial 22 is performed utilizing the same basic processing equipmentand steps as those used for patterning the first patternable low-kmaterial 18. Curing is also performed as described above. If thepatterned first low-k material was not previously cured, the curing stepused at this point would cure both the patterned first and second low-kmaterials. In the illustrated embodiment, the patterned second low-kmaterial has a surface whose height is greater than the height of theadjacent patterned low-k material. Variation to the size and shapes ofthe resultant patterned low-k material can be obtained and is within theknowledge of those skilled in the art.

The pattern provided by the patterned first and second low-k materialscan optionally be transferred into at least the underlying ARC 16 andoptional dielectric cap 14, if present. The resultant structure that isformed after performing pattern transfer forming patterned ARC 16′ andoptionally patterned dielectric cap 14′ is shown, for example, in FIG.1H. The pattern transfer is achieved by utilizing one or more etchingsteps. The one or more etching steps may include dry etching (i.e.,reactive-ion etching, ion beam etching, or laser etching), wet etching(i.e., using a suitable chemical etchant) or any combination thereof.Typically, a dry etching process such as reactive ion etching isemployed. In another embodiment, this etching step is performed prior tothe cure of the patterned second patternable low-k material.

The distance d₁, between the first patterned feature and the secondpattern feature is roughly half of the distance of similar features withone single exposure patterning. A third, fourth, etc. patterning can beconceived to further improve resolution by repeating the secondpatterning process described above.

Further semiconductor processing can now be performed to complete thefabrication of a desired structure or device. For example, furtherinterconnect processing can be used, such a formation of a diffusionbarrier and deposition of a conductive material can be performed to forman interconnect level of an interconnect structure.

Is it noted that the method of the present invention as illustrated inFIGS. 1A-1H enables high-resolution double patterning with a singlematerial (i.e., a patternable low-k dielectric material). Moreover, theinventive process illustrated above simplifies the double patterningfilm stack and process and also creates a fine permanent structure whichincludes the patternable low-k material in a patterned and cured state.Moreover, very small feature sizes can be obtained.

While the present invention has been particularly shown and describedwith respect to preferred embodiments thereof, it will be understood bythose skilled in the art that the foregoing and other changes in formsand details may be made without departing from the spirit and scope ofthe present invention. It is therefore intended that the presentinvention not be limited to the exact forms and details described andillustrated, but fall within the scope of the appended claims.

1. A method of forming a double patterned semiconductor structurecomprising: forming a first patternable low-k material above a surfaceof a material stack, wherein said first patternable low-k material is apolymer, a copolymer, a blend including at least two of any combinationof polymers and/or copolymers, wherein the polymers include one monomerand the copolymers include at least two monomers and wherein themonomers of the polymers and the monomers of the copolymers are selectedfrom a siloxane, silane, carbosilane, oxycarbosilane, silsesquioxane,alkyltrialkoxysilane, tetra-alkoxysilane, unsaturated alkyl substitutedsilsesquioxane, unsaturated alkyl substituted siloxane, unsaturatedalkyl substituted silane, an unsaturated alkyl substituted carbosilane,unsaturated alkyl substituted oxycarbosilane, carbosilane substitutedsilsesquioxane, carbosilane substituted siloxane, carbosilanesubstituted silane, carbosilane substituted carbosilane, carbosilanesubstituted oxycarbosilane, oxycarbosilane substituted silsesquioxane,oxycarbosilane substituted siloxane, oxycarbosilane substituted silane,oxycarbosilane substituted carbosilane, and oxycarbosilane substitutedoxycarbosilane; patterning said first patternable low-k material toprovide at least one opening in a first patterned low-k material abovesaid surface of said material stack; forming a second patternable low-kmaterial over said first patterned low-k material, wherein said secondpatternable low-k material is a polymer, a copolymer, a blend includingat least two of any combination of polymers and/or copolymers, whereinthe polymers include one monomer and the copolymers include at least twomonomers and wherein the monomers of the polymers and the monomers ofthe copolymers are selected from a siloxane, silane, carbosilane,oxycarbosilane, silsesquioxane, alkyltrialkoxysilane,tetra-alkoxysilane, unsaturated alkyl substituted silsesquioxane,unsaturated alkyl substituted siloxane, unsaturated alkyl substitutedsilane, an unsaturated alkyl substituted carbosilane, unsaturated alkylsubstituted oxycarbosilane, carbosilane substituted silsesquioxane,carbosilane substituted siloxane, carbosilane substituted silane,carbosilane substituted carbosilane, carbosilane substitutedoxycarbosilane, oxycarbosilane substituted silsesquioxane,oxycarbosilane substituted siloxane, oxycarbosilane substituted silane,oxycarbosilane substituted carbosilane, and oxycarbosilane substitutedoxycarbosilane; patterning said second patternable low-k material toprovide at least one opening in a second patterned low-k materialadjacent to, but not abutting the first patterned low-k material; andcuring at least the second patterned low-k material.
 2. The method ofclaim 1 further comprising transferring patterns provided by said firstand second patterned low-k materials into said material stack.
 3. Themethod of claim 1 further comprising curing the first patternable low-kmaterial after the patterning of said first patternable low-k materialand prior to forming the second patternable low-k material.
 4. Themethod of claim 1 wherein said curing is a thermal cure, an electronbeam cure, an ultra-violet (UV) cure, an ion beam cure, a plasma cure, amicrowave cure or a combination thereof.
 5. The method of claim 1wherein said material stack is located on a substrate and includes atleast an antireflective coating and optionally a dielectric cap, andsaid first patternable low-k material is formed directly on an uppersurface of the antireflective coating.
 6. The method of claim 5 whereinsaid antireflective coating is an inorganic antireflective coatingformed by vapor deposition and includes elements of M, C and H, whereinM is at least one of the elements of Si, Ge, B, Sn, Fe, Ta, Ti, Ni, Hfand La and, optionally, one of the elements of O, N, S and F.
 7. Themethod of claim 5 wherein said antireflective coating is an inorganicantireflective coating formed by liquid deposition and comprises apolymer that has at least one monomer unit having the formula M-R^(A),wherein M is at least one of the elements of Si, Ge, B, Sn, Fe, Ta, Ti,Ni, Hf and La and, optionally, one of the elements of O, N, S and F, andR^(A) is a chromophore.
 8. The method of claim 7 wherein said polymerfurther includes another monomer unit having the formula M′-R^(B),wherein M′ is at least one of the elements of Si, Ge, B, Sn, Fe, Ta, Ti,Ni, Hf and La and, optionally, one of the elements of O, N, S and F, andR^(B) is a cross-linking agent.
 9. The method of claim 8 wherein atleast one of M and M′ is further bonded to an organic ligand of theelements of C and H, a cross-linking component, a chromophore ormixtures thereof.
 10. The method of claim 5 wherein said antireflectivecoating undergoes a post deposition treatment selected from heattreatment, irradiation of electromagnetic wave, particle beam, plasmatreatment, chemical treatment through a gas phase or a liquid phase orany combination thereof.
 11. The method of claim 5 wherein saidantireflective coating is selected from an antireflective coating withuniform composition, an antireflective coating with graded compositionthrough the thickness direction, an antireflective coating that isself-developable during the pattering of the said first and said secondpatternable low-k materials.
 12. The method of claim 1 wherein saidpatterning of said first and said second patternable low-k materials isaccomplished by pattern-wise exposure through a mask with a lithographystepper or a scanner with an exposure light source of G-line, I-line(365 nm), DUV (248 nm, 193 nm, 157 nm, 126 nm), Extreme UV (13.4 nm), anelectron beam, an ion beam or a combination thereof.
 13. The method ofclaim 1 wherein said patterning of said first and said secondpatternable low-k materials is accomplished by pattern-wise directwriting without the use of a mask with light, electron beam, ion beam,scanning probe lithography or a combination thereof.
 14. The method ofclaim 1 wherein said patterning of said first and said secondpatternable low-k materials is accomplished with immersion lithographywith an exposure light source of 193 nm wavelength or below wherein aliquid having a refractive index greater than that of air is placed tofill the space between the final optical element of a lithographyprojection system and said first and said second patternable low-kmaterials.
 15. The method of claim 14 wherein said patterning of saidfirst and said second patternable low-k materials by immersionlithography with an exposure light source of 193 nm wavelength or belowis accomplished by forming a top coating directly on said first and saidsecond patternable low-k materials.
 16. A method of forming a doublepatterned semiconductor structure comprising: forming a firstpatternable low-k material on a surface of an inorganic antireflectivecoating, wherein said first patternable low-k material is a polymer, acopolymer, a blend including at least two of any combination of polymersand/or copolymers, wherein the polymers include one monomer and thecopolymers include at least two monomers and wherein the monomers of thepolymers and the monomers of the copolymers are selected from asiloxane, silane, carbosilane, oxycarbosilane, silsesquioxane,alkyltrialkoxysilane, tetra-alkoxysilane, unsaturated alkyl substitutedsilsesquioxane, unsaturated alkyl substituted siloxane, unsaturatedalkyl substituted silane, an unsaturated alkyl substituted carbosilane,unsaturated alkyl substituted oxycarbosilane, carbosilane substitutedsilsesquioxane, carbosilane substituted siloxane, carbosilanesubstituted silane, carbosilane substituted carbosilane, carbosilanesubstituted oxycarbosilane, oxycarbosilane substituted silsesquioxane,oxycarbosilane substituted siloxane, oxycarbosilane substituted silane,oxycarbosilane substituted carbosilane, and oxycarbosilane substitutedoxycarbosilane; patterning and curing said first patternable low-kdielectric material to provide a first structure having a firstpatterned and cured low-k material on the surface of the inorganicantireflective coating; forming a second patternable low-k material oversaid first structure, wherein said second patternable low-k material isa polymer, a copolymer, a blend including at least two of anycombination of polymers and/or copolymers, wherein the polymers includeone monomer and the copolymers include at least two monomers and whereinthe monomers of the polymers and the monomers of the copolymers areselected from a siloxane, silane, carbosilane, oxycarbosilane,silsesquioxane, alkyltrialkoxysilane, tetra-alkoxysilane, unsaturatedalkyl substituted silsesquioxane, unsaturated alkyl substitutedsiloxane, unsaturated alkyl substituted silane, an unsaturated alkylsubstituted carbosilane, unsaturated alkyl substituted oxycarbosilane,carbosilane substituted silsesquioxane, carbosilane substitutedsiloxane, carbosilane substituted silane, carbosilane substitutedcarbosilane, carbosilane substituted oxycarbosilane, oxycarbosilanesubstituted silsesquioxane, oxycarbosilane substituted siloxane,oxycarbosilane substituted silane, oxycarbosilane substitutedcarbosilane, and oxycarbosilane substituted oxycarbosilane; patterningsaid second patternable low-k material to provide a second structureincluding a second patterned low-k material adjacent to, but notabutting the first patterned cured low-k material; and curing the secondpatterned low-k material.
 17. The method of claim 16 further comprisingtransferring patterns provided by said first and said second patternedand cured low-k materials into the inorganic antireflective coating. 18.A double patterned semiconductor structure comprising: a first patternedand cured low-k material located on a portion of an antireflectivecoating; and a second patterned and cured low-k material located onanother portion of said antireflective coating, wherein said secondpatterned and cured low-k material is adjacent to, but not abutting saidfirst patterned and cured low-k dielectric material, said inorganicantireflective coating comprising (i) a material having elements of M, Cand H, wherein M is at least one of the elements of Si, Ge, B, Sn, Fe,Ta, Ti, Ni, Hf and La, or (ii) a polymer that has at least one monomerunit having the formula M-R^(A), wherein M is at least one of theelements of Si, Ge, B, Sn, Fe, Ta, Ti, Ni, Hf and La, and R^(A) is achromophore, and said first and said second patterned and cured low-kdielectrics comprise a same or different patternable low-k materialcomprising a polymer, a copolymer, a blend including at least two of anycombination of polymers and/or copolymers, wherein the polymers includeone monomer and the copolymers include at least two monomers and whereinthe monomers of the polymers and the monomers of the copolymers areselected from a siloxane, silane, carbosilane, oxycarbosilane,silsesquioxane, alkyltrialkoxysilane, tetra-alkoxysilane, unsaturatedalkyl substituted silsesquioxane, unsaturated alkyl substitutedsiloxane, unsaturated alkyl substituted silane, an unsaturated alkylsubstituted carbosilane, unsaturated alkyl substituted oxycarbosilane,carbosilane substituted silsesquioxane, carbosilane substitutedsiloxane, carbosilane substituted silane, carbosilane substitutedcarbosilane, carbosilane substituted oxycarbosilane, oxycarbosilanesubstituted silsesquioxane, oxycarbosilane substituted siloxane,oxycarbosilane substituted silane, oxycarbosilane substitutedcarbosilane, and oxycarbosilane substituted oxycarbosilane.
 19. Thedouble patterned semiconductor structure of claim 18 wherein saidinorganic antireflective coating comprises said polymer, and saidpolymer further includes another monomer unit having the formulaM′-R^(B), wherein M′ is at least one of the elements of Si, Ge, B, Sn,Fe, Ta, Ti, Ni, Hf and La and, optionally, one of the elements of O, N,S and F, and R^(B) is a cross-linking agent.
 20. The double patternedsemiconductor structure of claim 19 wherein at least one of M and M′ isfurther bonded to an organic ligand of the elements of C and H, across-linking component, a chromophore or mixtures thereof.
 21. Thedouble patterned semiconductor structure of claim 18 wherein said firstand said second patterned and cured low-k dielectric materials areseparated by a distance that is roughly half of the distance of similarfeatures with one single exposure patterning.